Isolated Tin(IV) Active Sites for Highly Efficient Electroreduction of CO2 to CH4 in Neutral Aqueous Solution

Abstract

AbstractThe development of efficient electrocatalysts with non‐copper metal sites for electrochemical CO2 reduction reactions (eCO2RR) to hydrocarbons and oxygenates is highly desirable, but still a great challenge. Herein, a stable metal–organic framework (DMA)4[Sn2(THO)2] (Sn‐THO, THO6− = triphenylene‐2,3,6,7,10,11‐hexakis(olate), DMA = dimethylammonium) with isolated and distorted octahedral SnO62− active sites is reported as an electrocatalyst for eCO2RR, showing an exceptional performance for eCO2RR to the CH4 product rather than the common products formate and CO for reported Sn‐based catalysts. The partial current density of CH4 reaches a high value of 34.5 mA cm−2, surpassing most reported copper‐based and all non‐Cu metal‐based catalysts. Our experimental and theoretical results revealed that the isolated SnO62− active site favors the formation of key *OCOH species to produce CH4 and can greatly inhibit the formation of *OCHO and *COOH species to produce *HCOOH and *CO, respectively.