Electron-distribution control via Pt/NC and MoC/NC dual junction:Boosted hydrogen electro-oxidation and theoretical study

The scarcity,high cost and susceptibility to CO of Platinum severely restrict its application in alkaline hydrogen oxidation reaction(HOR).Hybridizing Pt with other transition metals provides an effective strategy to modulate its catalytic HOR performance,but at the cost of mass activity due to the coverage of modifiers on Pt surface.Herein,we constructed dual junctions'Pt/nitrogen-doped carbon(Pt/NC)andδ-MoC/NC to modify electronic structure of Pt via interfacial electron transfer to acquire Pt-MoC@NC catalyst with electron-deficient Pt nanoparticles,simultaneously endowing it with high mass activity and durability of alkaline HOR.Moreover,the unique structure of Pt-MoC@NC endows Pt with a high COtolerance at 1,000 ppm CO/H_(2),a quality that commercial Pt-C catalyst lacks.The theoretical calculations not only confirm the diffusion of electrons from Pt/NC to Mo C/NC could occur,but also demonstrate the negative shift of Pt d-band center for the optimized binding energies of*H,*OH and CO.

新工科视域下地方特色轻工行业人才培养路径的探索——以温州大学制笔行业人才培养为例

轻工业新工科人才培养是关系国民经济发展和人民生活质量提高的重要课题。本文针对轻工业中尚未设置本科专业的制笔行业人才培养问题,在特色新工科人才培养的产业、技术、学科和人才培育基础上,探索实践了交叉强基、科教强新、产教强能的制笔行业新工科人才培养模式,并通过持续改进获得了较好的成效,可为其他高等院校实施特色行业新工科人才培养提供借鉴。

Recent advances in solar-driven CO_(2) reduction over g-C_(3)N_(4)-based photocatalysts

The persistent increase of CO_(2) levels in the atmosphere,already exceeding 400 ppm,urges the exploration of CO_(2) emission reduction and recycling technologies.Ideally,photocatalytic conversion of CO_(2) into valuable hydrocarbons realizes solar-to-chemical energy conversion,which is a desirable“kill two birds with one stone”strategy;namely,CO_(2) photoreduction can simultaneously tackle energy shortage and keep global carbon balance.Graphitic carbon nitride(g-C_(3)N_(4))working on CO_(2) reduction reaction deserves a highlight not only for the metal-free feature that endows it with low cost,tunable electronic structure,and easy fabrication properties but also because of its strong reduction ability.The present review concisely summarizes the latest advances of g-C_(3)N_(4)-based photocatalysts toward CO_(2) reduction.It starts with the discussion of thermodynamics and dynamics aspects of the CO_(2) reduction process.Then the modification strategies to promote g-C_(3)N_(4)-based photocatalysts in CO_(2) photoreduction have been discussed in detail,including surface functionalization,molecule structure engineering,crystallization,morphology engineering,loading cocatalyst,and constructing heterojunction.Meanwhile,the intrinsic factors affecting CO_(2) reduction activity and selectivity are analyzed and summarized.In the end,the challenges and prospects for the future development of highly g-C_(3)N_(4)-based photocatalysts in CO_(2) reduction are also presented.

Synergistic regulation of hydrophobicity and basicity for copper hydroxide-derived copper to promote the CO_(2)electroreduction reaction

A simple method was proposed to activate alkaline Cu(OH)_(2)with an acidic ionomer,Nafion,to regulate its surface microenvironment,including hydrophobicity and local basicity.In particular,the direct complete neutralization reaction between Cu(OH)_(2)and Nafion in aqueous solution induces the exposing of vast anions which can exclude the in-situ-formed hydroxides and raise the local basicity.Remarkably,the optimal Nafionactivated Cu(OH)_(2)-derived Cu can efficiently suppress the hydrogen evolution reaction(HER)and improve the selectivity for multi-carbon products in the CO_(2)electroreduction reaction(eCO_(2)RR).The H2 Faradaic efficiency(FE)decreased to 11%at a current density of 300 mA/cm2(−0.76 V vs.RHE)in a flow cell,while the bare one with H2 had an FE of 40%.The total eCO_(2)RR FE reaches as high as 83%,along with an evidently increased C2H4 FE of 44%as compared with the bare one(24%),and good stability(8000 s),surpassing that of most of the reported Cu(OH)_(2)-derived Cu.The experimental and theoretical results both show that the strong hydrophobicity and high local basicity jointly boosted the eCO_(2)RR as acquired by felicitously introducing ionomer on the Cu(OH)_(2)-derived Cu surface.

Nano-single-crystal-constructed submicron MnCO_(3) hollow spindles enabled by solid precursor transition combined Ostwald ripening in situ on graphene toward exceptional interfacial and capacitive lithium storage

Hollow structuring has been identified as an effective strategy to enhance the cycling stability of electrodes for rechargeable batteries due to the outstanding volume expansion buffering efficiency,which motivates ardent pursuing on the synthetic approaches of hollow materials.Herein,an intriguing route,combining solid precursor transition and Ostwald ripening(SPTOR),is developed to craft nano single-crystal(SC)-constructed MnCO_(3) submicron hollow spindles homogeneously encapsulated in a reduced graphene oxide matrix(MnCO_(3) SMHSs/rGO).It is noteworthy that the H-bonding interaction between Mn_(3)O_(4) nanoparticles(NPs)and oxygen-containing groups on GO promotes uniform anchoring of Mn_(3)O_(4) NPs on GO,mild reductant ascorbic acid triggers the progressive solid-to-solid transition from Mn_(3)O_(4) NPs to MnCO_(3) submicron solid spindles(SMSSs)in situ on GO,and the Ostwald ripening process induces the gradual dissolution of interior polycrystals of MnCO_(3) SMSSs and subsequent recrystallization on surface SCs of MnCO_(3) SMHSs.Remarkably,MnCO_(3) SMHSs/rGO delivers a 500th lithium storage capacity of 2023 mAh g^(-1) at 1000 mAg^(-1),which is 10 times higher than that of MnCO_(3) microspheres/rGO fabricated from a conventional Mn^(2+)salt precursor(202 mAh g^(-1)).The ultrahigh capacity and ultralong lifespan of MnCO_(3) SMHSs/rGO can be primarily attributed to the superior reaction kinetics and reversibility combined with exceptional interfacial and capacitive lithium storage capability,enabled by the fast ion/electron transfer,large specific surface area,and robust electrode pulverization inhibition efficacy.Moreover,fascinating in-depth lithium storage reactions of MnCO_(3) are observed such as the oxidation of Mn^(2+)in MnCO_(3) to Mn^(3+)in charge process after long-term cycles and the further lithiation of Li_(2)CO_(3) in discharge process.As such,the Carbon Energy.SPTOR approach may represent a viable strategy for crafting various hollow functional materials with metastable nanomaterials as precursors.

Low‐temperature synthesis of graphitic carbon‐coated silicon anode materials

We report the synthesis of a high‐performance graphitic carbon‐coated silicon(Si@GC)composite material for lithium‐ion batteries via a scalable production route.Porous Si is produced from the magnesiothermic reduction of commercial silica(SiO2)precursor followed by low‐temperature graphitic carbon coating using glucose as the precursor.The obtained Si@GC composite achieves an excellent reversible specific capacity of 1195 mAh g−1 and outstanding cycle stability.The thick Si@GC anode(3.4 mg cm^−2)in full cells with commercial lithium iron phosphate cathode delivers a remarkable performance of 800 mAh g^−1 specific capacity and 2.7 mAh cm^−2 areal capacity as well as 93.6%capacity retention after 200 cycles.

Heterointerface engineering of assembled CoP_(2) on N-modified carbon as efficient trifunctional electrocatalysts for Zn-Air batteries and overall water splitting

Enhancing catalytic activity through modulating the interaction between N-doped carbon and metal phosphides clusters is an effective approach.Herein,the electronic structure modulation of CoP_(2) supported N-modified carbon(CoP_(2)/NC)has been designed and prepared as efficient electrocatalysts for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER).Notably,CoP_(2)/NC-1 catalyst exhibits impressive performance in alkaline media,with an ORR half-wave potential of 0.84 V,as well as OER and HER overpotentials of 290 and 129 mV(at 10 mA·cm^(−2)),respectively.In addition,CoP_(2)/NC-1 produces a power density as high as 172.9 mW·cm^(−2),and excellent reversibility of 100 h at 20 mA·cm^(−2) in home-made Zn-air batteries.The experimental results demonstrate that the synergistic interactions between N modified carbon substrate and CoP_(2) material significantly enhance the kinetics of ORR,OER,and HER.Density functional theory(DFT)calculations reveal the strong electrons redistribution of CoP_(2) induced by high-density N atoms at the interface,thus optimizing the key intermediates and significantly lower the energy barrier of reactions.These electronic adjustments of CoP_(2) greatly enhance its kinetics of ORR/OER/HER,leading to faster reactions.This study provides profound insights into the specific modification of CoP_(2) by N-doped carbon,enabling the construction of efficient catalysts.

Lattice-distorted Pt wrinkled nanoparticles for highly effective hydrogen electrocatalysis

Modulating Pt surfaces through the introduction of lattice distortion emerges as immensely effective strategy that enhances the kinetics of alkaline hydrogen evolution and oxidation processes.In this study,we fabricated lattice-distorted Pt wrinkled nanoparticles(LD-Pt WNPs)for efficient hydrogen electrocatalysis.The LD-Pt WNPs not only outperform the Pt/C benchmark in hydrogen oxidation reaction,achieving an excellent mass-specific current of 968.5 mA·mg_(Pt)^(-1)(9 times that of Pt/C),but also demonstrate outstanding hydrogen evolution reaction activity with a small overpotential of 58.0 mV.Comprehensive experiments and density functional theory calculations reveal that lattice defects introduce an abundance of unsaturated coordination atoms while modifying the d-band center of Pt.This dual effect optimizes the binding strength of crucial H and OH intermediates,leading to a significant reduction in the energy barrier of the reaction bottleneck,commonly known as the Volmer step.This work unveils a fresh viewpoint on projecting and developing high efficiency electrocatalysts through defect engineering.

Highly selective and efficient electroreduction of CO_(2) in water by quaterpyridine derivative‐based molecular catalyst noncovalently tethered to carbon nanotubes

A disubstituted quaterpyridine based cobalt complex non‐covalently tethered to multiwalled carbon nanotube(MWCNT)substrate,forming a hybrid catalyst,Co‐qpyCOOH/CNT,catalyzed the conversion of CO_(2) to CO under aqueous conditions.At an optimal and uniform loading,it exhibited remarkable catalytic activity,near‐exclusive selectivity,and high stability towards the formation of CO.At a mere cathodic potential of−0.65 V versus RHE(η=0.54 V),it achieved a high partial current density of−6.7 mA/cm^(2) and a F.E.CO=100%.In addition,with 20 h of stable operation,hydrogen evolution remained practically undetected.Its hybrid structure due to noncovalent immobilization on MWCNT imparted the intrinsic activity and much‐needed stability in performance whereas‒COOH groups may stabilize the intermediates by acting as H‐bond donors,promoting catalytic activity.Tethering to a conductive solid substrate and tuning of the second sphere of coordination played an important role in its performance to achieve desired reduction product with high selectivity and activity.

Unprecedently low thermal conductivity of unique tellurium nanoribbons

Tellurene,probably one of the most promising two-dimensional(2D)system in the thermoelectric materials,displays ultra-low thermal conductivity.However,a linear thickness-dependent thermal conductivity of unique tellurium nanoribbons in this study reveals that unprecedently low thermal conductivity can be achieved via well-defined nanostructures of low-dimensional tellurium instead of pursuing dimension-reduced 2D tellurene.For thinnest tellurium nanoribbon with thickness of 144 nm,the thermal conductivity is only∼1.88±0.22 W·m^(−1)·K^(−1) at room temperature.It’s a dramatic decrease(45%),compared with the well-annealed high-purity bulk tellurium.To be more specific,an expected thermal conductivity of tellurium nanoribbons is even lower than that of 2D tellurene,as a result of strong phonon-surface scattering.We have faith in low-dimensional tellurium in which the thermoelectric performance could realize further breakthrough.

Structure engineering of PtCu_(3)/C catalyst from disordered to ordered intermetallic compound with heat-treatment for the methanol electrooxidation reaction

Platinum based alloys are hereinto the mostly used methanol oxidation catalysts.However,there are limited ways to improve the methanol oxidation reaction(MOR)performance of catalysts in terms of both activity and stability.Herein we developed a simple heat-treatment method to synthesize PtCu_(3)/C intermetallic compound catalyst with lattice compression.The as-prepared PtCu_(3)/C-1000 exhibited high specific activity of 3.23 mA·cm^(-1) and mass activity of 1,200 mA·mgPt^(-1),which is much higher than the PtCu_(3)/C-untreated and commercial Pt/C catalysts,respectively.The XAS and DFT results shows the high activity of the catalyst towards MOR comes from the tightening of the Pt-M bond,which leads to the decrease of Fermi energy level and the make it difficulty in adsorbing carbon intermediates,thus releasing more active sites to promote the improvement of MOR performance.Moreover,the PtCu_(3)/C-1000 shows better stability which is due to the surface-rich Pt prevents Cu from dissolution.