A Minireview on the Role of Cocatalysts in Semiconductor-Based Photocatalytic CH₄ Conversion

Abstract

Converting earth-abundant CH 4 to value-added feedstocks for chemical industry is an intriguing approach for utilization of carbon resource. However, the high inertness of CH 4 makes its catalytic conversion one of the holy grails and suffers from intense energy consumption in a traditional conversion process. The recently developed semiconductor-based photocatalytic processes operated at mild conditions shine light on the way to achieve efficient CH 4 conversion driven by only clean solar energy. In this review, we discuss the advancements in semiconductor-based photocatalytic CH 4 conversion and highlight the roles of cocatalysts, which are the key components in hybrid photocatalysts, in augmenting catalytic performance. Furthermore, the future research efforts on cocatalysts are proposed for promoting photocatalytic CH 4 conversion. Review pubs.acs.org/EF

2022 Pioneers in Energy Research: Jinhua Ye

“…There are five articles on the topic of decarbonization. In the review by Xiong et al, the advancements in semiconductor-based photocatalytic CH 4 conversion were discussed and the perspectives on co-catalysts for promoting the photoactivity were proposed . Zhang’s group presented a PdNi bimetallic catalyst derived from layered double hydroxide for light-driven steam methane reforming .…”

“…based photocatalytic CH 4 conversion were discussed and the perspectives on co-catalysts for promoting the photoactivity were proposed. 53 Zhang's group presented a PdNi bimetallic catalyst derived from layered double hydroxide for light-driven steam methane reforming. 54 Dai and Fu investigated the effects on three different shapes of the CeO 2 surface on photothermal CO 2 methanation.…”

Review on CeO2-Based Photocatalysts for Photocatalytic Reduction of CO2: Progresses and Perspectives

“…Fossil fuels provide energy for the development and prosperity of human society while emitting large amounts of carbon dioxide. Carbon dioxide (CO 2 ) is a key greenhouse gas, and its steady annual increase in the atmosphere has contributed to climate change. − Sea level rise, altered ocean currents, and extreme weather are just a few of the climate problems it has spawned, all of which pose serious threats to the long-term viability of human civilization. Energy security and environmental pollution are two of the most pressing issues in the world today, and the vigorous development of renewable energy sources is a major way to address these issues while also addressing the growing tension between ecological damage and resource constraints. − While low-carbon energy’s share has grown, national-level economic growth data shows that the world economy is still highly reliant on fossil fuels, the burning of which will contribute to the continued increase in CO 2 emissions. − The necessity of accelerating the pace of energy transition and ensuring energy security is therefore all the more urgent at this time.…”

Au–Pd Tandem Photocatalysis for Nonoxidative Coupling of Methane toward Ethylene

“…11,12 Because the products of the oxidative CH 4 activation, such as CH 3 OH, CO, C 2 H 4 , and C 2 H 6 , are more reactive than CH 4 , the overoxidation of CH 4 is almost unavoidable, leading to unsatisfactory product selectivity. 13 NOCM avoids this overoxidation while producing multicarbon products. 14 Currently, the predominant product of photocatalytic NOCM is ethane (C 2 H 6 ).…”

“…Methane (CH 4 ), being widely available, is a potential building block for the production of synthetic fuels and value-added chemicals. − However, the strong C–H bonds with low polarizability and the low electron affinity make the CH 4 upconversion one of the chemical “Holy Grails”. − Traditional thermocatalytic CH 4 activation operates at a high temperature and pressure, consuming substantial amounts of fossil fuels and releasing greenhouse gases. , Photocatalytic CH 4 activation using solar energy as the sole energy input has been considered a promising approach to achieve green conversion of CH 4 . In general, CH 4 activation can be divided into two types, i.e., oxidative activation and nonoxidative coupling of methane (NOCM). , Because the products of the oxidative CH 4 activation, such as CH 3 OH, CO, C 2 H 4 , and C 2 H 6 , are more reactive than CH 4 , the overoxidation of CH 4 is almost unavoidable, leading to unsatisfactory product selectivity . NOCM avoids this overoxidation while producing multicarbon products .…”