Direct photocatalytic conversion of methane to value-added chemicals

Photocatalysis is a promising approach to directly convert methane to value-added chemicals and fuels under mild conditions and in a sustainable manner. The direct and selective production of liquid oxygenates and higher hydrocarbons have been realized in photocatalytic methane conversion under aerobic or anaerobic conditions. The elegant construction of semiconductor materials and the reasonable utilization of cocatalysts allow precise control of overoxidation and efficient generation of the desired products. The fundamental understanding of the mechanism of photocatalytic methane conversion can contribute to the development of new pathways for energy-efficient methane conversion. Direct conversion of methane to value-added chemicals provides a promising alternative to industrial energy-intensive processes, but still faces many technological and economical challenges. Heterogeneous photocatalysis possesses great promise to drive direct methane conversion under mild conditions. In this review, we present the latest advances in direct photocatalytic conversion of methane to liquid oxygenates and higher hydrocarbons, with an emphasis on the strategies for the rational design of photocatalysts to improve the activity and selectivity of the desired products, and discuss the current challenges and our perspectives on opportunities for further development of photocatalytic systems that can enable highly selective and efficient conversion of methane to valuable chemicals. Direct conversion of methane to value-added chemicals provides a promising alternative to industrial energy-intensive processes, but still faces many technological and economical challenges. Heterogeneous photocatalysis possesses great promise to drive direct methane conversion under mild conditions. In this review, we present the latest advances in direct photocatalytic conversion of methane to liquid oxygenates and higher hydrocarbons, with an emphasis on the strategies for the rational design of photocatalysts to improve the activity and selectivity of the desired products, and discuss the current challenges and our perspectives on opportunities for further development of photocatalytic systems that can enable highly selective and efficient conversion of methane to valuable chemicals. the ratio of the number of reacted electrons to the number of incident photons. It is a common a criterion for evaluating the efficiency of a photocatalyst in photocatalysis. a transition metal or metal oxide that can accept photogenerated electrons or holes from semiconductor and provide active sites for redox reactions. an endothermic reaction in which methane is transformed into hydrogen and higher hydrocarbons such as ethane (2CH4 → H2 + C2H6, ΔG0298K = 68.6 kJ mol–1). constructed by a platinum electrode into a solution of 1 M strong acid solution protons and bubbling pure hydrogen gas through the solution at a pressure of one atmosphere and a temperature of 25°C. It is used as a reference electrode to determine the potentials of reactions. an exothermic reaction in which methane is reacted with oxygen to produce ethane and/or ethene (4CH4 + O2 → 2C2H6 + 2H2O, ΔG0298K = –320 kJ mol–1; 2CH4 + O2 →C2H4 + 2H2O, ΔG0298K = –288 kJ mol–1). an exothermic reaction in which methane is reacted with oxygen to produce methanol (2CH4 + O2 → 2CH3OH, ΔG0298K = –223 kJ mol–1). a strongly endothermic reaction in which methane is reacted with water to produce hydrogen and carbon monoxide (CH4 + H2O → 3H2 + CO, ΔG0298K = 142 kJ mol–1).