Construction And Electrocatalytic Performance Of Carbon Cloth In-situ Supported Cu-Co,Cu-Ni Catalyst

Nowdays,with the tremendous growth of demand for energy,depletion of fossil fuels and worsened environmental pollution,it is necessary to develop eco-friendly,renewable energy sources.Hydrogen is one of the most ideal alternative energy carrier because of its clean,sustainable,and regenerative nature.With the advantages of low cost and high effciency,electrochemical overall water splitting?OWP?is a promising approach to produce hydrogen with high purity.However,the practical application of OWP for mass production of hydrogen is greatly hindered by the large overpotential required in an electrolyzer arising from two half reactions in OWP,namely,cathodic hydrogen evolution reaction?HER?and anodic oxygen evolution reaction?OER?.Currently,noble metal-based catalysts,such as Pt-based materials and IrO₂,RuO₂ remain the benchmark electrocatalysts for HER and OER,respectively.Nevertheless,their widespread use in OWP is restricted by scarcity,exorbitant price,and poor durability.In this regard,developing effcient nonprecious materials for OWP and especially bifunctional electrocatalysts,effective for both HER and OER,is highly desirable providing a new avenue.Based on the above concept,we developed a 3D integrated architecture composed of CuCoN_x-based porous nanosheet arrays grown on a carbon cloth?CC?with a conductive nitrogen-doped carbon shell?NC@CuCo₂N_x/CC?as bifunctional electrocatalysts for OWP.The resulting NC@CuCo₂N_x/CC structure exhibited remarkable electrocatalytic performance for both HER and OER in alkaline medium.To reach the current density of 10 mA/cm²,the overpotential is only 105 mV for HER and 230 mV for OER.Taking advantage of this excellent bifunctional activity,a high-performance two-electrode electrolyzer for OWP was constructed,which can achieve a current density of 10 mA/cm² at a voltage less than 1.62 V.The enhanced electrocatalysis activity results from the synergistic interaction between CuCoN_x and N-doped carbon shell.The porous nanosheet array architecture also provided a large active surface area for ion and molecule diffusion,facilitating rapid electron transportation.Furthermore,the suitable adsorption energies of key species can be modulated as revealed from the density functional theory?DFT?calculations.We have successfully synthesized the three-dimensional?3D?copper-nickel phosphides nanosheets array?CuNi₂P/CC?on carbon cloth by a simple hydrothermal method and high temperature phosphating method,the material can be directly used as electrocatalyst for overall water splitting.The resulting CuNi₂P/CC exhibited remarkable electrocatalytic performance for both HER and OER in 1.0 KOH electrolyte.To reach the current density of 10 mA/cm²,the overpotential is only 168mV for HER and 330 mV for OER.The corresponding Tafel slope value is 72mV/dec and 75 mV/dec,respectively.For the NC@CuCo₂N_x/CC catalyst,taking advantage of this excellent OER performance,we studied the preparation of benzaldehyde by selective electrochemical oxidation?ECO?of benzyl alcohol.Experiments were run in H-type cell separated by a Nafon-117 membrane with a Pt sheet as cathode and NC@CuCo₂N_x/CC as anode.The 1.0 M KOH containing 15 mM benzyl alcohol was used in the anode compartment,whereas 1.0 M KOH was used in the cathode compartment,the volume of the electrolyte in two compartment is all 10 mL.A certain amount of TEMPO was also employed in anode to decrease the electrochemical voltage and promote the ECO reaction.The selective ECO of benzyl alcohol with high yield?96%?and selectivity of benzaldehyde??95%?at a constant current of 15 mA.