Proton Capture Strategy for Enhancing Electrochemical CO2 Reduction on Atomically Dispersed Metal-Nitrogen Active Sites*.

Xinyue Wang,Zhongjian Li,Ling Shuai,Lecheng Lei,Ming Qiu,Yang Hou,Siyu Yao,Bin Yang,Xiahan Sang,Chung‐Li Dong,Liming Dai,Jianguo Lu

doi:10.1002/anie.202100011

Abstract

Electrocatalysts play a key role in accelerating the sluggish electrochemical CO2 reduction (ECR) involving multi-electron and proton transfer. We now develop a proton capture strategy by accelerating the water dissociation reaction catalyzed by transition-metal nanoparticles (NPs) adjacent to atomically dispersed and nitrogen-coordinated single nickel (Ni-Nx ) active sites to accelerate proton transfer to the latter for boosting the intermediate protonation step, and thus the whole ECR process. Aberration-corrected scanning transmission electron microscopy, X-ray absorption spectroscopy, and calculations reveal that the Ni NPs accelerate the adsorbed H (Had ) generation and transfer to the adjacent Ni-Nx sites for boosting the intermediate protonation and the overall ECR processes. This proton capture strategy is universal to design and prepare for various high-performance catalysts for diverse electrochemical reactions even beyond ECR.

Highlights

Electrochemical CO2 reduction (ECR) has been widely studied as a mean of energy storage to tackle the current energy and environmental challenges[1]
It has been previously revealed that the delocalization of unpaired electron in 3d orbital to allow for efficient charge transfer from TM center to CO2 molecule was beneficial to the activation of adsorbed CO2 species and responsible for the high intrinsic ECR activity of TM-NC electrocatalysts[5]
As can be seen from above, we have developed a proton capture strategy by hybridizing Ni NPs with atomically dispersed Ni-Nx species on a carbon matrix to enhance the Had capture for the protonation intermediate step, and the whole ECR process

Summary

Introduction

Electrochemical CO2 reduction (ECR) has been widely studied as a mean of energy storage to tackle the current energy and environmental challenges[1]. As a typical product that can be highly energy-efficiently generated through a two-electron transfer process, CO gas from ECR is very attractive for a wide range of industrial applications, including as an essential feedstock for Fischer-Tropsch synthesis[2,3]. This technology still suffers multiple disadvantages, including the thermodynamic stability of CO2, complex competitive reactions, and high-energy consumption. Transition metal (Fe, Co, Ni, etc.) and nitrogen co-doped carbon (TM-NC) based electrocatalysts were demonstrated to hold great potential as a class of efficient earth-abundant ECR catalysts[4,5,6,7]. TM-NC catalysts still suffer from inefficient and sluggish reaction kinetics associated with the proton-coupled electron transfer process of CO2 to CO8, which seriously hinder their practical applications

Methods

Results

Conclusion