Plasma-electrified up-carbonization for low-carbon clean energy

Low-value, renewable, carbon-rich resources, with different biomass feedstocks and their derivatives as typical examples, represent virtually inexhaustive carbon sources and carbon-related energy on Earth. Upon conversion to higher-value forms (referred to as “up-carbonization” here), these abundant feedstocks provide viable opportunities for energy-rich fuels and sustainable platform chemicals production. However, many of the current methods for such up-carbonization still lack sufficient energy, cost, and material efficiency, which affect their economics and carbon-emissions footprint. With external electricity precisely delivered, discharge plasmas enable many stubborn reactions to occur under mild conditions, by creating locally intensified and highly reactive environments. This technology emerges as a novel, versatile technology platform for integrated or stand-alone conversion of carbon-rich resources. The plasma-based processes are compatible for integration with increasingly abundant and cost-effective renewable electricity, making the whole conversion carbon-neutral and further paving the plasma-electrified up-carbonization to be performance-, environment-, and economics-viable. Despite the chief interest in this emerging area, no review article brings together the state-of-the-art results from diverse disciplines and underlies basic mechanisms and chemistry underpinned. As such, this review aims to fill this gap and provide basic guidelines for future research and transformation, by providing an overview of the application of plasma techniques for carbon-rich resource conversion, with particular focus on the perspective of discharge plasmas, the fundamentals of why plasmas are particularly suited for up-carbonization, and featured examples of plasma-enabled resource valorization. With parallels drawn and specificity highlighted, we also discuss the technique shortcomings, current challenges, and research needs for future work.