Dopant-tuned stabilization of intermediates promotes electrosynthesis of valuable C3 products

Tao‐Tao Zhuang ,Xue Wang,Fengwang Li,Dae‐Hyun Nam ,Alexander H Ip ,Colin P O’brien ,Wan Ru Leow,Shu‐Hong Yu ,David Sinton,Hui Li ,Yanwei Lum,Rui Wu,Christine M Gabardo ,Ziyun Wang,Tao Peng,Zhiqin Liang ,Bin Chen,Xiaojing Liu ,Jun Li,Yi Li,Tsun‐Kong Sham ,Joshua Wicks,Edward H Sargent

doi:10.1038/s41467-019-12788-0

Abstract

The upgrading of CO2/CO feedstocks to higher-value chemicals via energy-efficient electrochemical processes enables carbon utilization and renewable energy storage. Substantial progress has been made to improve performance at the cathodic side; whereas less progress has been made on improving anodic electro-oxidation reactions to generate value. Here we report the efficient electroproduction of value-added multi-carbon dimethyl carbonate (DMC) from CO and methanol via oxidative carbonylation. We find that, compared to pure palladium controls, boron-doped palladium (Pd-B) tunes the binding strength of intermediates along this reaction pathway and favors DMC formation. We implement this doping strategy and report the selective electrosynthesis of DMC experimentally. We achieve a DMC Faradaic efficiency of 83 ± 5%, fully a 3x increase in performance compared to the corresponding pure Pd electrocatalyst.

Highlights

The upgrading of CO2/CO feedstocks to higher-value chemicals via energy-efficient electrochemical processes enables carbon utilization and renewable energy storage
We evaluated the effect of applied potential on the reaction using the computational hydrogen electrode of Nørskov and co-workers[25] and applied 1 V vs. SHE toward dimethyl carbonate (DMC) electrocatalytic formation[16]
Using extended X-ray absorption fine structure (EXAFS) to acquire information on atomic bonding near the Pd atom (Fig. 3b and c), we found that Pd–B has a lower Pd–Pd coordination number (Pd: 10.4, Pd–B: 9.7) and longer Pd–Pd interatomic distance (Pd: 2.747 Å, Pd–B: 2.776 Å) compared to that of pure Pd (Fig. 3d, e) during electrocatalytic DMC production when B is present (Supplementary Fig. 9)

Summary

Introduction

The upgrading of CO2/CO feedstocks to higher-value chemicals via energy-efficient electrochemical processes enables carbon utilization and renewable energy storage. We find that, compared to pure palladium controls, boron-doped palladium (Pd-B) tunes the binding strength of intermediates along this reaction pathway and favors DMC formation. We implement this doping strategy and report the selective electrosynthesis of DMC experimentally. In anodic chemical upgrade reactions, a important challenge is to achieve selective electro-oxidation to the desired valuable product, instead of overoxidizing the inputs all the way to CO2. Our findings motivate us to attempt the doping of Pd to tune intermediate binding energies to favor DMC formation, a strategy we implemented experimentally, allowing us to achieve high-faradaic-efficiency conversion to DMC. This work suggests further potential in interstitial doping to promote oxidation-based carbon upgrade reactions using renewable feedstocks

Methods

Results

Conclusion