Hydrogen energy is a zero-carbon,high-density energy carrier,predominantly derived from fossil fuels such as natural gas or coal.As the global push toward achieving"carbon peak and neutrality"goals intensifies and the transition to low-carbon energy acceler-ates,the importance of sustainable hydrogen energy is becoming increasingly evident.However,the mismatch between current hydrogen production technologies and the growing energy demand is becoming more pronounced.Single solar-driven hydrogen production technolo-gies remain limited by factors such as high production costs,technological immaturity,and inadequate infrastructure,preventing them from replacing fossil fuel-based methods on a large scale in the near term.The highly endothermic nature of the methane reforming reac-tion enables solar-driven methane reforming to absorb solar thermal energy up to 23％of the higher heating value of methane,by which solar energy can also be stored and converted to chemical energy,increasing the proportion of solar energy in hydrogen energy while simul-taneously reducing carbon emissions in hydrogen production.Therefore,solar-driven natural gas reforming technology for hydrogen produc-tion is expected to play a pivotal role in the near-to mid-term.However,the simple integration of traditional SMR with concentrating so-lar technology still requires reaction temperatures of 800 to 1 000 ℃ and high concentration ratios exceeding 1 000.These requirements re-sult in large radiative and convective heat losses,and fail to address critical technical challenges,such as the complexity and high carbon emissions of traditional SMR system.Lowering the reaction temperature of methane reforming through product separation by Le Chatelier's principle has the potential to overcoming the bottleneck in integrating with solar concentrating technologies.Furthermore,the synergistic hydrogen production and decarbonization at the origin of methane conversion could effectively address the challenges of high temperature,high energy consumption and high carbon emissions associated with traditional methane reforming.The advancements in solar methane re-forming technology for hydrogen production and decarbonization from both thermodynamic and kinetic perspectives were reviewed.The trends of development of conventional solar methane reforming from concentrating solar technologies,reforming reactors and hydrogen pro-duction systems were analyzed.The fundamental reasons underlying critical challenges of conventional solar methane reforming technologies were also analyzed,such as high reaction temperatures,high irreversible losses in solar concentration and high energy consumption.Fur-thermore,new principles and methods from the perspective of reaction process design was focused on that can simultaneously reduce reac-tion temperature,improve product selectivity,and promote the synergistic conversion of hydrogen and carbon constituents.Methane refor-ming with single-product separation of CO2 or hydrogen using sorbent or membrane can reduce reaction temperatures to 500-600 ℃.A further reduction to 400 ℃ or below can be achieved by sequentially separating two or more target products,reaching near-complete meth-ane conversion and H2 & CO2 product selectivity under isothermal and atmospheric pressure conditions with solar trough concentrators,sig-nificantly reducing reaction temperature and energy consumption for hydrogen production and decarbonization while greatly simplifying and consolidating the hydrogen production system with a high level of integration.Under the new circumstances of vigorously developing renew-able energy and promoting low-carbon energy transition,innovations in thermodynamic approaches,process design,and hydrogen produc-tion methods offer the potential for traditional methane reforming to achieving deep integration with solar thermal technologies.Such inte-gration is expected to open up broader prospects for breakthroughs in sustainable hydrogen technologies in the near-to mid-term.
solar energymid-temperaturemethane reforminghydrogendecarbonization
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