Critical role of hydrogen sorption kinetics in electrocatalytic CO2 reduction revealed by on-chip in situ transport investigations

Abstract

Precise understanding of interfacial metal−hydrogen interactions, especially under in operando conditions, is crucial to advancing the application of metal catalysts in clean energy technologies. To this end, while Pd-based catalysts are widely utilized for electrochemical hydrogen production and hydrogenation, the interaction of Pd with hydrogen during active electrochemical processes is complex, distinct from most other metals, and yet to be clarified. In this report, the hydrogen surface adsorption and sub-surface absorption (phase transition) features of Pd and its alloy nanocatalysts are identified and quantified under operando electrocatalytic conditions via on-chip electrical transport measurements, and the competitive relationship between electrochemical carbon dioxide reduction (CO2RR) and hydrogen sorption kinetics is investigated. Systematic dynamic and steady-state evaluations reveal the key impacts of local electrolyte environment (such as proton donors with different pKa) on the hydrogen sorption kinetics during CO2RR, which offer additional insights into the electrochemical interfaces and optimization of the catalytic systems.

Defect engineering of two-dimensional materials for advanced energy conversion and storage

“…Electrocatalytic CO 2 reduction reaction (CO 2 RR) is a very feasible strategy, which can realize the conversion of CO 2 to high-value chemicals using renewable electricity. [309][310][311][312] Generally, the CO 2 RR mainly contains three steps: the chemical adsorption of CO 2 on active sites, the electron and/or proton transfer to break C-O bonds and/or form C-H bonds, and the desorption of reduction products. [313][314][315] Among these processes, the second step is a proton-coupled multi-step reaction potentially containing varied electron transfer pathways.…”

The role of crystallinity of palladium nanocrystals in ROS generation and cytotoxicity induction

“…Pd, on the other hand, is generally considered to be an excellent catalytic agent for reduction, often involved in hydrogenation processes with its strong affinity for hydrogen atoms. [53][54][55] Herein, the hydrogen evolution reaction (HER) was used to evaluate the capability of H + absorption.…”

Role of Hydride Formation in Electrocatalysis for Sustainable Chemical Transformations

“…76 In materials like Pd, PdH x formation results in a well-known increase in electronic resistance that can be probed via electrochemical transport spectroscopy measuring a secondary source−drain current for in situ assessment of hydride formation. 54…”

“…This range in FEs could also be due, in part, to the ability of unique morphologies and environments to form hydrides (where defective nanostructures form hydrides more readily). Palladium hydride formation also depends on the proton donating capacity of the electrolyte, being fastest in strongly acidic environments …”

“…Hydrogen permeation through a membrane can also be quantified by a similar approach driving the hydrogen oxidation reaction on a probing anode . In materials like Pd, PdH x formation results in a well-known increase in electronic resistance that can be probed via electrochemical transport spectroscopy measuring a secondary source–drain current for in situ assessment of hydride formation …”