Engineering oxygen vacancies on Tb-doped ceria supported Pt catalyst for hydrogen production through steam reforming of long-chain hydrocarbon fuels

Steam reforming of long-chain hydrocarbon fuels for hydrogen production has received great attention for thermal management of the hypersonic vehicle and fuel-cell application.In this work,Pt catalysts supported on CeO_(2)and Tb-doped CeO_(2)were prepared by a precipitation method.The physical structure and chemical properties of the as-prepared catalysts were characterized by powder X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Raman spectroscopy,H_(2)temperature programmed reduction,and X-ray photoelectron spectroscopy.The results show that Tb-doped CeO_(2)supported Pt possesses abundant surface oxygen vacancies,good inhibition of ceria sintering,and strong metal-support interaction compared with CeO_(2)supported Pt.The catalytic performance of hydrogen production via steam reforming of long-chain hydrocarbon fuels(n-dodecane)was tested.Compared with 2Pt/CeO_(2),2Pt/Ce_(0.9)Tb_(0.1)O_(2),and 2Pt/Ce_(0.5)Tb_(0.5)O_(2),the 2Pt/Ce_(0.7)Tb_(0.3)O_(2)has higher activity and stability for hydrogen production,on which the conversion of n-dodecane was maintained at about 53.2%after 600 min reaction under 700℃at liquid space velocity of 9 ml·g^(-1)·h^(-1).2Pt/CeO_(2)rapidly deactivated,the conversion of n-dodecane was reduced to only 41.6%after 600 min.

Ultralow charge-discharge voltage gap of 0.05 V in sunlight-responsive neutral aqueous Zn-air battery

Rechargeable neutral aqueous zinc-air batteries(ZABs)are a promising type of energy storage device with longer operating life and less corrosiveness compared with conventional alkaline ZABs.However,the neutral ZABs normally possess poor oxygen evolution reactions(OERs)and oxygen reduction reactions performance,resulting in a large charge–discharge voltage gap and low round-trip efficiency.Herein,we demonstrate a sunlight-assisted strategy for achieving an ultralow voltage gap of 0.05 V in neutral ZABs by using the FeOOH-decorated BiVO4(Fe-BiVO4)as an oxygen catalyst.Under sunlight,the electrons move from the valence band(VB)of Fe-BiVO_(4) to the conduction band producing holes in VB to promote the OER process and hence reduce the overpotential.Meanwhile,the photopotential generated by the Fe-BiVO_(4) compensates a part of the charging potential of neutral ZABs.Accordingly,the energy loss of the battery could be compensated via solar energy,leading to a record-low gap of 0.05 V between the charge and discharge voltage with a high round-trip efficiency of 94%.This work offers a simple but efficient pathway for solar-energy utilization in storage devices,further guiding the design of high energy efficiency of neutral aqueous ZABs.

Colorless to black switching with high contrast ratio via the electrochemical process of a hybrid organic-inorganic perovskite

Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.

An intermittent lithium deposition model based on CuMnbimetallic MOF derivatives for composite lithium anode with ultrahigh areal capacity and current densities

Recently,three-dimensional(3D)conductive frameworks have been chosen as the host for composite lithium(Li)metal anode because of their exceptional electrical conductivity and remarkable thermal and electrochemical stability.However,Li tends to accumulate on the top of the 3D frameworks with homogenous lithiophilicity and Li dendrite still growth.This work firstly designed a bimetallic metal-organic framework(MOF)(CuMn-MOF)derived Cu_(2)O and Mn_(3)O_(4) nanoparticles decorated carbon cloth(CC)substrates(CC@Cu_(2)O/Mn_(3)O_(4))to fabricate a composite Li anode.Thanks to the synergistic effects of lithiophilic Cu_(2)O and Mn_(3)O_(4),the CC@Cu_(2)O/Mn_(3)O_(4)@Li symmetrical cell can afford a prolonged cycling lifespan(1400 h)under an ultrahigh current density and areal capacity(6 mA·cm^(-2)/6 mAh·cm^(-2)).When coupled with the LiFePO_(4)(LFP)cathode,the LFP||CC@Cu_(2)O/Mn_(3)O_(4)@Li full cell demonstrated a superior performance of 89.7 mAh·g^(-1) even at an extremely high current density(10 C).Furthermore,it can also be matched well with LiNi_(0.5)Co^(0).2Mn_(0.3)O_(2)(NCM523)cathode.Importantly,to explain the excellent performances of the CC@Cu_(2)O/Mn_(3)O_(4)@Li composite anode,an intermittent model was also proposed.This study offers a novel model that can enhance our comprehension of the Li deposition behavior and pave the way to attain stable and safe Li metal anodes by employing bimetallic MOF-derived materials to construct 3D frameworks.

Wettability-driven synergistic resistance of scale and oil on robust superamphiphobic coating

Disgusting deposits(e.g.,scale and crude oil)in daily life and industrial production are always serious problems,posing great threats to the safety and economic development.However,most of developed coatings can only conquer one part of these deposits such as superhydrophobic coatings possess antiscaling capacity but would adhere crude oil.To integrate scale resistance with oil repellence,we herein report a robust superamphiphobic(SAB)coating simultaneously reducing pollution of scale and oil for extended period of time(two weeks with over 98%reduction).Compared with single role of superhydrophobic and amphiphilic surfaces,the SAB coating can not only inhibit interfacial nucleation of scale but also reduce the adhesion of formed scale and polluted oil.The durability of the SAB coating is evaluated via mechanical tests(sandpaper abrasion,tape stripping and sand falling)and chemical corrosion(corrosive liquid immersing),revealed by sustainable high contact angles and low contact angle hysteresis of water and oil.The universality of this strategy can be further confirmed by adding different particles like kaolin,Al_(2)O_(3),and SiO_(2),resisting multiple types of scale(i.e.,CaSO_(4),BaSO_(4)and MgCO_(3))and oil(i.e.,glycerol,glycol,and mineral oil).Therefore,this study provides an ideal avenue for resisting scale and oil,which may be used for conquering the complexity of application environments(e.g.,oil production and transportation).

An intermittent lithium deposition model based on bimetallic MOFs derivatives for dendrite-free lithium anode with ultrahigh areal capacity

In the development of 3D conductive frameworks for lithium metal anode(LMA),two models have been proposed:top growth model and bottom-up growth model.However,Li tends to accumulate on the top of these 3D frameworks with homogenous lithiophilicity(top growth)and Li dendrite still forms.To address this issue,some researchers have focused on developing 3D frameworks with gradient lithio-philicity,which realized bottom-up growth of Li.Nevertheless,partial Li nucleation sites on the top of these frameworks were missed.Inspired by the two models talked above,this work firstly proposed a novel intermittent lithiophilic model for lithium deposition.To demonstrate the feasibility of this model,a bimetallic metal-organic frameworks derived ZnMn_(2)O_(4)-MnO nanoparticles were grown on carbon cloth for LMA.It can cycle stably under ultra-high current and areal capacity(10 mA/cm^(2),10 mAh/cm^(2)).The in-situ optical microscopy(OM)was conducted to observe the Li deposition behavior,no dendrite was found during 80 h in ester-based electrolyte while the pure Li only cycled for 2h.What is more,it can also be well-coupled with LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathode and solid-state electrolyte,which further prove the advantages of the intermittent model for the development of LMAs with high safety and high energy density.

Scalable and Robust Bio-inspired Organogel Coating by Spraying Method Towards Dynamic Anti-scaling

Scaling usually causes serious problems in daily life and industrial production.Currently,developing passive anti-scaling coatings has shown promises to overcome this problem.In this work,we fabricated a scalable and robust bio-inspired organogel(BIO)coating,showing dynamic scale resistance in the oil/brine mixture.The oil layer of the BIO coating was utilized as a barrier to inhibit scale nucleation and reduce scale adhesion.The mechanical strength of the coating was optimized by regulating nanoparticle contents.Moreover,the universality of scale resistance was demonstrated by varying the types of nanoparticles,oils and scales.Compared with commercial pipeline materials,such as copper,this BIO coating significantly reduces scale deposition after 240-h scaling test(ca.93%reduction).Therefore,this study designs scalable and robust organogel coatings for sustainable scale resistance,which may be used for practical application in oil production.

Superhydrophilic nickel hydroxide ultrathin nanosheets enable high-performance asymmetric supercapacitors

Superhydrophilic surfaces have been applied for supercapacitor;however,during energy storage reaction,how the wettability affects the process of electrochemical reaction specifically is still unclear.Herein,we demonstrate superhydrophilic surface for promotion of electrochemical reactions by liquid affinity and further explain the mechanism,where the transition of the wettability state caused by the change in surface free energy is the main reason for the obvious increase in specific capacitance.Through citric acid assistance strategy,an intrinsically hydrophobic Ni(OH)_(2)thick nanosheets(HNHTNs,16 nm)can be transitioned into superhydrophilic Ni(OH)_(2)ultrathin nanosheets(SNHUNs,6.8 nm),where the water contact angle was 0°and the surface free energy increased from 8.6to 65.8 mN·m^(-1),implying superhydrophilicity.Compared with HNHTNs,the specific capacitance of SNHUNs is doubled:from 1230 F·g^(-1)(HNHTNs)to 2350 F·g^(-1)(2A·g^(-1))and,even at 20 A·g^(-1),from 833 F·g^(-1)(HNHTNs)to 1670 F·g^(-1).The asymmetric capacitors assembled by SNHUNs and activated carbon show 52.44 Wh·kg^(-1)at 160W·kg^(-1)and excellent stability with~90%retention after5000 cycles(~80%retention after 9500 cycles).The promotion of electrochemical performances is ascribed to the change of surface wettability caused by surface free energy,which greatly increase affinity of electrode to the surrounding liquid environment to reduce the interface resistance and optimize the electron transport path.

Co-POM@MOF-derivatives with trace cobalt content for highly efficient oxygen reduction

A simple and effective method for constructing highly efficient oxygen reduction catalysts with trace amount of isolated cobalt was firstly developed by the pyrolysis of Co-centered polyoxometalate@metalorganic framework (Co-POM@MOF).The Co-centered polyoxometalate ([Co W_(12)O_(40)]^(6-)) was confined in the well-defined void space of ZIF-8 to achieve homogeneous dispersion of polyoxoanions,where the isolated Co centers were well surrounded by the W-O shell and ZIF-8 framework.The Co-POM@MOF-derived N-doping porous carbon (Co-W-NC) with trace cobalt content was facilely prepared by the pyrolysis of the Co-POM@MOF under Ar atmosphere.The single dispersion of polyoxoanions in the metal-organic framework with complete separation of Co center surrounding by W-O shell and ZIF-8 framework ensures the uniform dispersion of Co atoms,confirmed by the Fourier transform extended X-ray absorption fine structure measurement.The Co-W-NC composite catalysts exhibit high performance for oxygen reduction reactions with a half-wave potential of 0.835 V in 0.1 mol/L KOH solution with excellent durability,which is much superior to that of the control samples derived from the[PW_(12)O_(40)]@ZIF-8,and the commercial Pt/C.This work highlights a new insight for constructing highly efficient catalysts via the introduction of metal-centered polyoxometalate into metal-organic framework following the high temperature treatment process.