Copper Phyllosilicate-Derived Cu Catalyst for the Water–Gas Shift Reaction: Insight into the Role of Cu+–Cu0 and Reaction Mechanism

Cu-based catalysts have been extensively researched for hydrogen production via water–gas shift (WGS, CO+H 2 O↔CO 2 +H 2 ) reaction. Yet, the catalyst easily suffers from performance degradation due to Cu + /Cu 0 transformation and particle aggregation. Herein, copper phyllosilicate with different morphologies, i.e., tubular and lamellar, was fabricated by a modified hydrothermal method for the WGS reaction. Compared with the catalyst derived from lamellar copper phyllosilicate (30Cu/SiO 2 -L), the one derived from the tubular phyllosilicate (30Cu/SiO 2 -T) demonstrates better performance due to the high Cu + /(Cu 0 +Cu + ) ratio. In situ characterizations were conducted to unveil the transformation between Cu + and Cu 0, which is highly correlated to the CO and H 2 O activation. Cu + is primarily responsible for the activation of CO, while Cu 0 mainly facilitates the dissociation of H 2 O. The results show that 30Cu/SiO 2 -T follows the redox mechanism, where CO reduces Cu + to Cu 0 and H 2 O oxidizes Cu 0 to Cu +, maintaining the reaction cycle.