Recent progress on copper catalysts with different surface states for CO_(2)electroreduction

The electrochemical carbon dioxide reduction reaction(eCO_(2)RR),which converts CO_(2)into various hydrocarbons or alcohols,has been extensively researched because it promises a sustainable energy economy.However,only copper(Cu)can currently achieve stable and efficient hydrocarbon conversion in the eCO_(2)RR.Therefore,understanding the catalytic mechanisms and summarizing the research progress on synthesis strategies of Cu catalysts are essential for the eCO_(2)RR.This paper reviews Cu catalysts with different surface states of Cu catalysts:oxide-derived Cu,Cu nanoparticles,Cu single atoms,and Cu nanoclusters.It then reviews the development and progress of different Cu-catalyst preparation methods in recent years,focusing on the activity and selectivity of materials.Besides revealing the tendencies of catalytic selection and deep reactive mechanisms of Cu catalysts with four different surface states,this review can guide the subsequent construction of catalysts and provides an understanding of catalytic mechanisms.

Engineering active sites on hierarchical transition bimetal oxyhydride/bicarbonate heterostructure for oxygen evolution catalysis in seawater splitting

Designing efficient and stable electrocatalysts to improve the oxygen evolution reaction(OER)with slow reaction kinetics is essential to improve hydrogen production from electrochemical water splitting.This research has prepared a series of FeOOH/Ni(HCO_(3))_(2)heterostructured materials(denoted as FeOOH_(x)/Ni(HCO_(3))_(2))by a one-pot solvothermal method.The OER performance of the catalysts was maximized by finely tuning the content of different components,heterogeneous interfaces,and electronic structures.Specifically,the obtained FeOOH0.60/Ni(HCO_(3))_(2)heterostructured nanosheets had the lowest overpotential of 216 mV at a current density of 10 mA·cm^(−2)and were stable at a high current density of 100 mA·cm^(−2)for more than 96 h.The excellent OER activity and stability were still maintained in alkaline natural seawater(1 M KOH+seawater).When FeOOH0.60/Ni(HCO_(3))_(2)was used as the anode for water splitting,the electrolyzer provided a current density of 10 mA·cm^(−2)at a very low cell voltage of 1.51 V(1.56 V at 1 M KOH+seawater)and exhibited superior stability.The outstanding OER performance is ascribed to the synergistic effect of FeOOH and Ni(HCO_(3))_(2)upon heterostructure formation,as well as the altered electronic structure between the heterogeneous interfaces and the suitable hierarchical nanosheet morphology facilitating many active sites.This work provides a promising direction for improving the electrocatalytic activity of nickel-based catalysts in seawater splitting,which has important implications for both hydrogen economy and environmental remediation.