Metal-based Heterogeneous Electrocatalysts for Electrochemical Reduction of Carbon Dioxide to Methane: Progress and Challenges

Electrochemical reduction of carbon dioxide (CO2ER) has attracted enormous research interest owing to the feasibility to consume the excessive CO2 in atmosphere arising from overconsumption of fossil fuels and store the chemical energy in value-added chemicals. The conversion of CO2 into methane (CH4) is of great importance, and recent advance has allowed the design and utilisation of effective electrocatalysts with improved electrocatalytic performance regarding product selectivity and Faradaic efficiency. In this mini-review, we discuss the recent progress and challenges of metal-based heterogeneous electrocatalyst for CO2ER into CH4 by starting with fundamental mechanisms and designing principles of effective electrocatalysts. In the following sections, we present several successful demonstrations and analyze the effect and contribution arising from their chemical composition, facet, size, and other characters. Some challenges and promising strategies are discussed finally.