SnO2/Sn3O4异相工程促进二氧化碳电催化还原生成甲酸

Heterophase engineering of SnO2/Sn3O4 drives enhanced carbon dioxide electrocatalytic reduction to formic acid

锡(Sn)基电催化剂可以以可持续能源为动力将二氧化碳转化为甲酸,因而获得越来越多的关注,但其催化二氧化碳还原反应(CO2RR)的能力仍然达不到商业应用要求,因此开发高效Sn基催化剂极为重要.本文利用简单的水热过程,首次设计合成得到以Sn3O4为主的具有高密度相界面的片状Sn O2/Sn3O4异相催化剂.实验和理论模拟结果表明,异相界面的电荷再分布和内建电场促进了CO2的吸附和HCOO*的形成,加速了催化剂和反应物之间的电荷转移,最终大大提高了Sn O2/Sn3O4异相催化剂对CO2RR的内在活性.同时,在CO2RR过程中原位生成的多孔结构和金属Sn改善了反应物和电子在Sn O2/S n3O4片内的传质和传荷.Sn O2/S n3O4异相催化剂对CO2RR表现出较高的活性和选择性,提高了CO2还原电流密度.在-0.9 VRHE时甲酸的法拉第效率为88.3%,且对CO2RR具有长期的耐受性.该研究结果表明,异相界面工程是调节先进催化剂性能的一种有效策略.

Sn-based electrocatalysts have been gaining increasing attention due to their potential contribution in the conversion of CO2 into HCOOH driven by sustainable energy sources;however,their actual capability to catalyze CO2 reduction reaction(CO2RR)still cannot meet the requirements of commercial-scale applications.Therefore developing Snbased catalyst is of vital importance.Herein,the sheet-like heterophase Sn O2/Sn3O4 with a high density of phase interfaces has been first engineered by a facile hydrothermal process,with Sn3O4 as the dominant phase.The evidences from experiments and theoretical simulation indicate that the charge redistribution and built-in electric field at heterophase interfaces boost CO2 adsorption and HCOO*formation,accelerate the charge transfer between the catalysts and reactants,and ultimately greatly elevate the intrinsic activity of the heterophase Sn O2/Sn3O4 towards CO2 RR.Meanwhile,the in-situ generated porous structure and metal Sn during CO2 RR improve the mass transmission within the interlayer volume and the conductivity of Sn O2/Sn3O4.The heterophase Sn O2/Sn3O4 displays high activity and selectivity for CO2 RR,achieving an improvement in CO2 reduction current density,88.3%Faradaic efficiency of HCOOH conversion at-0.9 VRHE,along with a long-term tolerance in CO2 RR.This study demonstrates that heterophase interface engineering is an efficient strategy to regulate advanced catalysts for different applications.