Metal oxides heterojunction derived Bi-In hybrid electrocatalyst for robust electroreduction of CO_(2) to formate

Electrochemical reduction of Bi-based metal oxides is regarded as an effective strategy to rationally design advanced electrocatalysts for electrochemical CO_(2)reduction reaction(CO_(2)RR).Realizing high selectivity at high current density is important for formate production,but remains challenging.Herein,the BiIn hybrid electrocatalyst,deriving from the Bi2O3/In2O3heterojunction(MOD-Biln),shows excellent catalytic performance for CO_(2)RR.The Faradaic efficiency of formate(FEHCOO-) can be realized over 90% at a wide potential window from-0.4 to-1.4 V vs.RHE,while the partial current density of formate(jHCOO-) reaches about 136.7 mA cm^(-2)at-1.4 V in flow cell without IR-compensation.In additio n,the MOD-Biln exhibits superior stability with high selectivity of formate at 100 mA cm^(-2).Systematic characterizations prove the optimized catalytic sites and interface charge transfer of MOD-Biln,while theoretical calculation confirms that the hybrid structure with dual Bi/In metal sites contribute to the optimal free energy of*H and*OCHO intermediates on MOD-Biln surface,thus accelerating the formation and desorption step of*HCOOH to final formate production.Our work provides a facile and useful strategy to develop highly-active and stable electrocatalysts for CO_(2)RR.

Electronic structural engineering of bimetallic Bi-Cu alloying nanosheet for highly-efficient CO_(2) electroreduction and Zn-CO_(2) batteries

Regulating the electronic structure of Bi-based materials by alloying engineering is promising to promote the electrocatalytic activity,but it remains some challenges to be solved.In this study,a facile electrochemical co-deposition strategy is developed to synthesize the bimetallic Bi_(9)Cu_(1) alloy nanosheet on carbon cloth(Bi_(9)Cu_(1)/CC),which represents a novel self-supporting electrode for the electrocatalytic carbon dioxide(CO_(2))reduction reaction(CO_(2)RR).The Bi_(9)Cu_(1)/CC catalyst has achieved a remarkable catalytic performance with high Faradaic efficiencies(FE)of over 90%for formate at wide potentials from-0.7 to-1.2 V vs.reversible hydrogen electrode(RHE).Moreover,the reversible Zn-CO_(2) battery can be driven by Bi_(9)Cu_(1)/CC cathode with a largest power density of 1.4 mW·cm^(-2),and superior operating stability.The systematic characterizations and electrochemical results confirm that the improved catalytic active sites,the enhanced mass/charge transport and the optimal reaction kinetics of Bi nanosheet are realized for CO_(2)RR by Cu alloying.In situ attenuated total reflection infrared(ATR-IR)result confirms the bimetallic Bi-Cu active sites prefer to follow the^(*)OCHO conversion pathway.The density functional theory(DFT)calculations suggest that the Cu alloying contributes to the increased density of states near the Fermi surface of Bi and the optimized adsorption of^(*)OCHO intermediates on the Bi sites,resulting in the excellent catalytic performance.