Accelerating Oxygen Electrocatalysis Kinetics on Metal-Organic Frameworks via Bond Length Optimization

Metal-organic frameworks(MOFs)have been developed as an ideal platform for exploration of the relationship between intrinsic structure and catalytic activity,but the limited catalytic activity and stability has hampered their practical use in water splitting.Herein,we develop a bond length adjustment strategy for optimizing naphthalene-based MOFs that synthesized by acid etching Co-naphthalenedicarboxylic acid-based MOFs(donated as AE-CoNDA)to serve as efficient catalyst for water splitting.AE-CoNDA exhibits a low overpotential of 260 mV to reach 10 mA cm^(−2)and a small Tafel slope of 62 mV dec^(−1)with excellent stability over 100 h.After integrated AE-CoNDA onto BiVO_(4),photocurrent density of 4.3 mA cm^(−2)is achieved at 1.23 V.Experimental investigations demonstrate that the stretched Co-O bond length was found to optimize the orbitals hybridization of Co 3d and O 2p,which accounts for the fast kinetics and high activity.Theoretical calculations reveal that the stretched Co-O bond length strengthens the adsorption of oxygen-contained intermediates at the Co active sites for highly efficient water splitting.

Nanostructured Ternary Metal Tungstate-Based Photocatalysts for Environmental Purification and Solar Water Splitting:A Review

Visible-light-responsive ternary metal tungstate(MWO_4) photocatalysts are being increasingly investigated for energy conversion and environmental purification applications owing to their striking features, including low cost,eco-friendliness, and high stability under acidic and oxidative conditions. However, rapid recombination of photoinduced electron–hole pairs and a narrow light response range to the solar spectrum lead to low photocatalytic activity of MWO_4-based materials, thus significantly hampering their wide usage in practice. To enable their widespread practical usage, significant efforts have been devoted, by developing new concepts and innovative strategies. In this review, we aim to provide an integrated overview of the fundamentals and recent progress of MWO_4-based photocatalysts. Furthermore, different strategies, including morphological control, surface modification, heteroatom doping, and heterojunction fabrication, which are employed to promote the photocatalyticactivities of MWO_4-based materials, are systematically summarized and discussed. Finally, existing challenges and a future perspective are also provided to shed light on the development of highly efficient MWO_4-based photocatalysts.

Identification of the starting reaction position in the hydrogenation of (N-ethyl)carbazole over Raney-Ni

Hydrogenation of carbazole and N-ethylcarbazole over Raney-Ni catalyst were realized in the temperature range of 393-503 K. 4[H] adduct dominated the hydrogenation products and the formation of 2[H] adduct was the rate-limiting step during the period, in which the conversion of carbazole was less than 40%. The hydrogenation process followed pseudo-first-order kinetics and the hydrogenation activation energies of carbazole and N-ethylcarbazole were 90 kJ/mol and 115 kJ/mol, respectively. The reaction starting position as well as the pathway of the hydrogenation of （N-ethyl）carbazole were investigated by comparing the kinetic characteristics of hydrogen uptake of carbazole and N- ethylcarbazole. The results showed that the reaction was a stepwise hydrogenation process and the first H_2 was added to the C1 = C10 double bond in the hydrogenation.

Nitrogen-Doped Carbon-Encased Bimetallic Selenide for High-Performance Water Electrolysis

Demand of highly efficient earth-abundant transition metal-based electrocatalysts to replace noble metal materials for boosting oxygen evolution reaction(OER)is rapidly growing.Herein,an electrochemically exfoliated graphite(EG)foil supported bimetallic selenide encased in N-doped carbon(EG/(Co,Ni)Se2-NC)hybrid is developed and synthesized by a vapor-phase hydrothermal strategy and subsequent selenization process.The as-prepared EG/(Co,Ni)Se2-NC hybrid exhibits a core-shell structure where the particle diameter of(Co,Ni)Se2 core is about 70 nm and the thickness of N-doped carbon shell is approximately 5 nm.Benefitting from the synergistic effects between the combination of highly active Co species and improved electron transfer from Ni species,and N-doped carbon,the EG/(Co,Ni)Se2-NC hybrid shows remarkable electrocatalytic activity toward OER with a comparatively low overpotential of 258 mV at an current density of 10 mA cm?2 and a small Tafel slope of 73.3 mV dec?1.The excellent OER catalysis performance of EG/(Co,Ni)Se2-NC hybrid is much better than that of commercial Ir/C(343 mV at 10 mA cm?2 and 98.1 mV dec?1),and even almost the best among all previously reported binary CoNi selenide-based OER electrocatalysts.Furthermore,in situ electrochemical Raman spectroscopy combined with ex situ X-ray photoelectron spectroscopy analysis indicates that the superb OER catalysis activity can be attributed to the highly active Co-OOH species and modified electron transfer process from Ni element.

A Superaerophobic Bimetallic Selenides Heterostructure for Efficient Industrial-Level Oxygen Evolution at Ultra-High Current Densities

Cost-effective and stable electrocatalysts with ultra-high current densities for electrochemical oxygen evolution reaction(OER)are critical to the energy crisis and environmental pollution.Herein,we report a superaerophobic three dimensional(3D)heterostructured nanowrinkles of bimetallic selenides consisting of crystalline NiSe2 and NiFe2Se4 grown on NiFe alloy(NiSe2/NiFe2Se4@NiFe)prepared by a thermal selenization procedure.In this unique 3D heterostructure,numerous nanowrinkles of NiSe2/NiFe2Se4 hybrid with a thickness of ~100 nm are grown on NiFe alloy in a uniform manner.Profiting by the large active surface area and high electronic conductivity,the superaerophobic NiSe2/NiFe2Se4@NiFe heterostructure exhibits excellent electrocatalytic activity and durability towards OER in alkaline media,outputting the low potentials of 1.53 and 1.54 V to achieve ultra-high current densities of 500 and 1000 mA cm^−2,respectively,which is among the most active Ni/Fe-based selenides,and even superior to the benchmark Ir/C catalyst.The in-situ derived FeOOH and NiOOH species from NiSe2/NiFe2Se4@NiFe are deemed to be efficient active sites for OER.

Application of in-plasma catalysis and post-plasma catalysis for methane partial oxidation to methanol over a Fe_2O_3-CuO/γ-Al_2O_3 catalyst

Methane partial oxidation to methanol （MPOM） using dielectric barrier discharge over a Fe2O3-CuO/γ-Al2O3 catalyst was performed.The multicomponent catalyst was combined with plasma in two different configurations,i.e.,in-plasma catalysis （IPC） and post-plasma catalysis （PPC）.It was found that the catalytic performance of the catalysts for MPOM was strongly dependent on the hybrid configuration.A better synergistic performance of plasma and catalysis was achieved in the IPC configuration,but the catalysts packed in the discharge zone showed lower stability than those connected to the discharge zone in sequence.Active species,such as ozone,atomic oxygen and methyl radicals,were produced from the plasma-catalysis process,and made a major contribution to methanol synthesis.These active species were identified by the means of in situ optical emission spectra,ozone measurement and FT-IR spectra.It was confirmed that the amount of active species in the IPC system was greater than that in the PPC system.The results of TG,XRD,and N2 adsorption-desorption revealed that carbon deposition on the spent catalyst surface was responsible for the catalyst deactivation in the IPC configuration.

A Universal Principle to Accurately Synthesize Atomically Dispersed Metal–N_4 Sites for CO_2 Electroreduction

Atomically dispersed metal-nitrogen sites-anchored carbon materials have been developed as effective catalysts for CO2 electroreduction(CO2 ER),but they still suffer from the imprecisely control of type and coordination number of N atoms bonded with central metal.Herein,we develop a family of single metal atom bonded by N atoms anchored on carbons(SAs-M-N-C,M=Fe,Co,Ni,Cu)for CO2 ER,which composed of accurate pyrrole-type M-N4 structures with isolated metal atom coordinated by four pyrrolic N atoms.Benefitting from atomically coordinated environment and specific selectivity of M-N4 centers,SAs-Ni-N-C exhibits superior CO2 ER performance with onset potential of-0.3 V,CO Faradaic efficiency(F.E.) of 98.5%at-0.7 V,along with low Tafel slope of 115 mV dec-1 and superior stability of 50 h,exceeding all the previously reported M-N-C electrocatalysts for CO2-to-CO conversion.Experimental results manifest that the different intrinsic activities of M-N4 structures in SAs-M-N-C result in the corresponding sequence of Ni> Fe> Cu> Co for CO2 ER performance.An integrated Zn-CO2 battery with Zn foil and SAs-Ni-N-C is constructed to simultaneously achieve CO2-to-CO conversion and electric energy output,which delivers a peak power density of 1.4 mW cm-2 and maximum CO F.E.of 93.3%.

Ultrasmall Pt_(2)Sr alloy nanoparticles as efficient bifunctional electrocatalysts for oxygen reduction and hydrogen evolution in acidic media

Electrocatalytic oxygen reduction reaction(ORR)and hydrogen evolution reaction(HER)in acidic media are vital for the applications of renewable energy electrolyzers.However,the low mass activity of noble Pt urgently needs to be improved due to the strong binding energetics of oxygen species(*O)with Pt sites.Here we report fine PtxSr alloy(-2 nm)supported on N-doped carb on(NC)pyrolyzing from ZIF-8 as bifunctional electrocatalysts toward ORR and HER in acidic media.The representative Pt_(2)Sr/NC exhibits an onset potential of 0.94 V vs.RHE and half-wave potential of 0.84 V toward ORR,and a low over-potential of 27 mV(10 mA cm^(-2))toward HER,respectively.Significantly,the mass activities of Pt_(2)Sr/NC are 6.2 and 2.6 times higher than that of Pt/C toward ORR(at 0.9 V)and HER(at-30 mV),respectively.Simultaneously,Pt_(2)Sr/NC possesses a retention rate of 90.97%toward acidic ORR after 35000 s of continuous operation.Through density functional theory(DFT)calculations and X-ray photoelectron spectroscopy analysis,the incorporation of Sr into Pt forming Pt_(2)Sr alloy redistributes the electronic structures of Pt-Pt bonds,changing the rate-determining step for the ORR on Pt sites from the formation of*OH from*O to the generation of*OOH along with decreasing the energy barrier,which is also confirmed by the downshift of d band center.Meanwhile,the downshift of d band center also leads to the optimization of the adsorption energy(H*)with Pt,significantly improving Pt_(2)Sr/NC toward HER.

Bimetallic Oxyhydroxide as a High-Performance Water Oxidation Electrocatalyst under Industry-Relevant Conditions

Developing high-performing oxygen evolution reaction(OER)electrocatalysts under high-current operation conditions is critical for future commercial applications of alkaline water electrolysis for clean energy generation.Herein,we prepared a three-dimensional(3D)bimetallic oxyhydroxide hybrid grown on a Ni foam(NiFeOOH/NF)prepared by immersing Ni foam(NF)into Fe(NO_(3))_(3) solution.In this unique 3D structure,the NiFeOOH/NF hybrid was composed of crystalline Ni(OH)_(2) and amorphous FeOOH evenly grown on the NF surface.As a bimetallic oxyhydroxide electrocatalyst,the NiFeOOH/NF hybrid exhibited excellent catalytic activity,surpassing not only the other reported Ni–Fe based electrocatalysts,but also the commercial Ir/C catalyst.In situ electrochemical Raman spectroscopy demonstrated the active FeOOH and NiOOH phases involved in the OER process.Profiting from the synergy of Fe and Ni catalytic sites,the NiFeOOH/NF hybrid delivered an outstanding OER performance under challenging industrial conditions in a 10.0 mol·L^(-1) KOH electrolyte at 80℃,requiring potentials as small as 1.47 and 1.51 V to achieve the super-high catalytic current densities of 100 and 500mA∙cm^(-2),respectively.

High performance n^+p-Si/Ti/NiS_xO_y photocathode for photoelectrochemical hydrogen evolution in alkaline solution

Silicon, as a promising semiconductor for fabricating photocathode toward photoelectrochemical hydrogen evolution reaction(PEC-HER), should be improved in light harvesting ability and catalytic kinetics to obtain high PEC performance. Herein, a novel amorphous Nickel Oxysulfide(NiS_xO_y) film is effectively integrated with a Ti protected n^+p-Si micropyramid photocathode by the electrodeposition method. The fabricated n^+p-Si/Ti/Ni SxOyphotocathode exhibits excellent PEC-HER performance with an onset potential of 0.5 V(at J =-0.1 mA/cm^2), a photocurrent density of-26 mA/cm^2 at 0 V vs. RHE, and long term stability of six hours in alkaline solution(pH ≈ 14). The synergy of unique n^+p-Si micropyramid architectures(omnidirectional broadband light harvesting ability), novel amorphous NiS_xO_y catalyst(high HER electrocatalytic activity and good optical transparency) results in the high performance of n^+pSi/Ti/Ni S_xO_y. This work offers a novel strategy for effectively integrating electrocatalysts with semiconductor to design efficient photoelectrode toward PEC water splitting.

Nanocarbon-Enhanced 2D Photoelectrodes:A New Paradigm in Photoelectrochemical Water Splitting

Solar-driven photoelectrochemical(PEC)water splitting systems are highly promising for converting solar energy into clean and sustainable chemical energy.In such PEC systems,an integrated photoelectrode incorporates a light harvester for absorbing solar energy,an interlayer for transporting photogenerated charge carriers,and a co-catalyst for triggering redox reactions.Thus,understanding the correlations between the intrinsic structural properties and functions of the photoelectrodes is crucial.Here we critically examine various 2D layered photoanodes/photocathodes,including graphitic carbon nitrides,transition metal dichalcogenides,layered double hydroxides,layered bismuth oxyhalide nanosheets,and MXenes,combined with advanced nanocarbons(carbon dots,carbon nanotubes,graphene,and graphdiyne)as co-catalysts to assemble integrated photoelectrodes for oxygen evolution/hydrogen evolution reactions.The fundamental principles of PEC water splitting and physicochemical properties of photoelectrodes and the associated catalytic reactions are analyzed.Elaborate strategies for the assembly of 2D photoelectrodes with nanocarbons to enhance the PEC performances are introduced.The mechanisms of interplay of 2D photoelectrodes and nanocarbon co-catalysts are further discussed.The challenges and opportunities in the field are identified to guide future research for maximizing the conversion efficiency of PEC water splitting.

纺织废水的处理:均相催化湿气氧化

我们进行了一系列的试验，并找到了在一定温度和压力下能提高纺织废水湿空气氧化反应速率的催化剂。废水的种类包括天然纤维脱浆废水、合成纤维脱浆废水和印染废水。实验结果表明：所有被试验的催化剂均能显著提高化学需氧量(COD)和总有机碳(TOC)去除率及总COD和TOC去除量。在所有测试的催化剂中，铜盐的效果最好。盐溶液中的阴离子在催化过程中起着十分重要的作用。硝酸根离子的催化效果比硫酸根离子要强。同样地，硝酸铜的催化性能比硫酸铜要强。不同金属盐的混合物的催化性能要强于单盐的催化性能。

Layered bismuth oxide/bismuth sulfide supported on carrageenan derived carbon for efficient carbon dioxide electroreduction to formate

Electrochemical reduction of carbon dioxide(CO_(2)ER)into formate plays a crucial role in CO_(2)conversion and utilization.However,it still faces the problems of high overpotential and poor catalytic stability.Herein,we report a hybrid CO_(2)ER electrocatalyst composed of layered bismuth sulfide(Bi_(2)S_(3))and bismuth oxide(Bi_(2)O_(3))supported on carrageenan derived carbon(Bi-CDC)prepared by a combined pyrolysis with hydrothermal treatment.In such 3 D hybrid,layered Bi_(2)O_(3)and Bi_(2)S_(3)are uniformly grown on nanocarbon supports.Benefiting from strong synergistic effect between Bi_(2)O_(3)/Bi_(2)S_(3)and nanocarbon,Bi-CDC-1:2 displays a high Faradic efficiency(FE)of>80%for formate production in the range of-0.9 V to-1.1 V with the maximum formate FE of 85.6%and current density of 14.1 mA·cm^(-2) at-1.0 V.Further,a positive onset potential of-0.5 V,a low Tafel slope of 112.38 mV·dec^(-1),and a slight performance loss during long-term CO_(2)ER tests are observed on Bi-CDC-1:2.Experimental results shows that the better CO_(2)ER performance of Bi-CDC-1:2 than that of Bi_(2)O_(3)can be attributed to the strong interfacial interactions between nanocarbons and Bi_(2)O_(3)/Bi_(2)S_(3).In situ ATR-FTIR measurements reveal that the rate-determining step in the CO_(2)ER is the formation of HCOO^(*) intermediated.Compared with carbon support,Bi-CDC-1:2 can promote the production of HCOO^(*) intermediate and thus promoting CO_(2)ER kinetic.

Enhanced hydrogen evolution from the face-sharing[RuO6]octahedral motif

Hampered by the ambiguous mechanism of hydrogen evolution reaction(HER)in basic media,the exploration of highly efficient catalytically active sites for alkaline HER is of significance.Herein,a metal oxide Sr_(4)Ru_(2)O_(9)engineering a face-sharing[RuO_(6)]octahedra motif was synthesized through the solid-state method,and served as HER electrocatalyst.Benefited from the Ru-Ru metallic bonding crossing the common plane,the H*adsorption and reaction energy barriers were optimized.Sr_(4)Ru_(2)O_(9)only required an ultra-small overpotential(η10)of 28 m V at a current density of 10 mA cm^(-2) for HER in 1.0 M KOH with an exceptional stability(180 hours),outperforming the commercial Pt/C(η10=38 mV).These findings suggest a fresh insight in designing novel active sites for electrocatalysis.

Correction to: A Universal Principle to Accurately Synthesize Atomically Dispersed Metal-N4 Sites for CO2 Electroreduction

In the original publication,the author name was incorrectly published as Xilin Wu.The correct author name should be Xi-Lin Wu,which is provided in this correction.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License,which permits use,sharing,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons licence,and indicate if changes were made.The images or other third party material in this article are included in the article’s Creative Commons licence,unless indicated otherwise in a credit line to the material.

Highly efficient electrosynthesis of H_(2)O_(2)in acidic electrolyte on metal-free heteroatoms co-doped carbon nanosheets and simultaneously promoting Fenton process

Recently electrochemical synthesis of H_(2)O_(2)through oxygen reduction reaction(ORR)via 2e^(-)pathway is considered as a green and on-site route.However,it still remains a big challenge for fabricating novel metal-free catalysts under acidic solutions,since it suffers from high overpotential due to the intrinsically week*OOH adsorption.Herein,a co-doped carbon nanosheet(O/N–C)catalyst toward regulating O and N content was synthesized for improving the selectivity and activity of H_(2)O_(2)electrosynthesis process.The O/N–C exhibits outstanding 2e-ORR performance with low onset potential of 0.4 V(vs.RHE)and a selectivity of 92.4%in 0.1 mol/L HClO_(4)solutions.The in situ electrochemical impedance spectroscopy(EIS)tests reveals that the N incorporation contributes to the fast ORR kinetics.The density functional theory(DFT)calculations demonstrate that the binding strength of*OOH was optimized by the co-doping of oxygen and nitrogen at certain content,and the O/N–C–COOH site exhibits a lower theoretical overpotential for H_(2)O_(2)formation than O–C–COOH site.Furthermore,the promoted kinetics for typical organic dye degradation in simultaneous electron-Fenton process on O/N–C catalyst was demonstrated particularly for broadening its environmental application.

Recent progress and perspective of electrochemical CO_(2) reduction towards C_(2)-C_(5) products over non-precious metal heterogeneous electrocatalysts

Electroreduction of carbon dioxide(CO_(2)ER)into value-added chemical compounds has presented as a promising route for renewable carbon cycle,which alleviates global warming concern.Compared with traditional C1 products,high-value multicarbon products converted from atmospheric CO_(2) via CO_(2)ER have attracted dramatic interest due to their significant economic efficiency,however desired catalytic selectivity of multicarbon products is difficult to achieve because of the high thermodynamic barriers and complex reaction pathways.To replace currently used precious-metal based catalysts,developing highly efficient and precious-metal-free CO_(2)ER catalysts based on earth abundant elements is the top priority to meet the requirements of industrialization.Although certain progress has been made,there are still few systematic reports on the non-precious metal heterogeneous(NPMH)CO_(2)ER electrocatalysts for efficient conversion of CO_(2) to multicarbon products.Herein,we summarize the latest research advances in recent developments of NPMH electrocatalysts,including nanostructured Cu,Cu-based bimetallic catalysts,Cu-based complexes,and carbon-based Cu-free catalysts for electroreduction of CO_(2) into high-value multicarbon products.The corresponding CO_(2)ER performances are discussed in the order of the types of multicarbon products,specifically for ethanol(C2H5OH),ethylene(C2H4),ethane(C2H6),acetic acid(CH3COOH),propanol(C3H7OH),and other O^(2+)products with a special attention paid to understand the structure-activity relationship.Moreover,key strategies and characterization techniques for catalytic mechanism insights,and unsolved issues and future trends for enhancing the CO_(2)ER performance of NPMH electrocatalysts are highlighted,which provides a constructive guidance on the development of CO_(2)ER electrocatalysts with high activity and selectivity for multicarbon products.

Bi/Bi2O3 nanoparticles supported on N-doped reduced graphene oxide for highly efficient CO2 electroreduction to formate

Electrocatalytic CO2 reduction(CO2 ER)into formate is a desirable route to achieve efficient transformation of CO2 to value-added chemicals,however,it still suffers from limited catalytic activity and poor selectivity.Herein,we develop a hybrid electrocatalyst composed of bismuth and bismuth oxide nanoparticles(NPs)supported on nitrogen-doped reduced graphene oxide(Bi/Bi2 O3/NrGO)nanosheets prepared by a combined hydrothermal with calcination treatment.Thanks to the combination of undercoordinated sites and strong synergistic effect between Bi and Bi2 O3,Bi/Bi2 O3/NrGO-700 hybrid displays a promoted CO2 ER catalytic performance and selectivity for formate production,as featured by a small onset potential of-0.5 V,a high current density of-18 mA/cm2,the maximum Faradaic efficiency of85%at-0.9 V,and a low Tafel slope of 166 mV/dec.Experimental results reveal that the higher CO2 ER performance of Bi/Bi2 O3/NrGO-700 than that of Bi NPs supported on NrGO(Bi/NrGO)can be due to the partial reduction of Bi2 O3 NPs into Bi,which significantly increases undercoordinated active sites on Bi NPs surface,thus boosting its CO2 ER performance.Furthermore,a two-electrode device with Ir/C anode and Bi/Bi2 O3/NrGO-700 cathode could be integrated with two alkaline batteries or a planar solar cell to achieve highly active water splitting and CO2 ER.

Co_(1-x)S embedded in porous carbon derived from metal organic framework as a highly efficient electrocatalyst for oxygen evolution reaction

Developing active, robust, and cost-efficient electrocatalysts is critical for oxygen evolution reaction(OER). Here, a novel composite catalyst of Co_(1-x)S embedded in porous dodecahedron carbon hybrid was synthesized by a two-step conversion protocol of a cobalt-based metal-organic framework(ZIF-67). The porous dodecahedron Co_(1-x)S@C composite catalyst was prepared by direct oxidation of ZIF-67 followed by sulfurization reaction. The Co_(1-x)S@C composite exhibit superior OER performance, including a low overpotential of 260 mV for 10 mA/cm2, a small Tafel slope of ~85 mV/dec, outstanding stability over 80 h and almost 100% Faradaic efficiency. The various material characterizations indicate that the excellent activity and strong stability of Co_(1-x)S@C might be attributed to good conductivity of Co_(1-x)S, mesoporous nanostructure, and synergistic effect of Co_(1-x)S encapsulated within porous carbon. This work provides a novel strategy for designing and synthesizing advanced composite

Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of CO_(2)in H_(2)-mediated microbial electrosynthesis

Microbial electrosynthesis is a promising alternative to directly convert CO_(2)into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic systems.However,problems arose that the conventional electrocatalysts for hydrogen evolution may produce extensive by-products of reactive oxygen species and cause severe metal leaching,both of which induce strong toxicity toward microorganisms.Moreover,poor stability of electrocatalysts cannot be qualified for long-term operation.These problems may result in poor biocompatibility between electrocatalysts and microorganisms.To solve the bottleneck problem,Co anchored on porphyrinic triazine-based frameworks was synthesized as the electrocatalyst for hydrogen evolution and further coupled with Cupriavidus necator H16.It showed high selectivity for a four-electron pathway of oxygen reduction reaction and low production of reactive oxygen species,owing to the synergistic effect of Co–Nx modulating the charge distribution and adsorption energy of intermediates.Additionally,low metal leaching and excellent stability were observed,which may be attributed to low content of Co and the stabilizing effect of metalloporphyrins.Hence,the electrocatalyst exhibited excellent biocompatibility.Finally,the microbial electrosynthesis system equipped with the electrocatalyst successfully converted CO_(2)to poly-β-hydroxybutyrate.This work drew up a novel strategy for enhancing the biocompatibility of electrocatalysts in microbial electrosynthesis system.