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

Abstract The development of efficient electrocatalysts with non‐copper metal sites for electrochemical CO 2 reduction reactions (eCO 2 RR) to hydrocarbons and oxygenates is highly desirable, but still a great challenge. Herein, a stable metal–organic framework (DMA) 4 [Sn 2 (THO) 2 ] (Sn‐THO, THO 6− = triphenylene‐2,3,6,7,10,11‐hexakis(olate), DMA = dimethylammonium) with isolated and distorted octahedral SnO 6 2− active sites is reported as an electrocatalyst for eCO 2 RR, showing an exceptional performance for eCO 2 RR to the CH 4 product rather than the common products formate and CO for reported Sn‐based catalysts. The partial current density of CH 4 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 SnO 6 2− active site favors the formation of key *OCOH species to produce CH 4 and can greatly inhibit the formation of *OCHO and *COOH species to produce *HCOOH and *CO, respectively.