Recent advances on hydrothermal carbonization of biomass for carbon-negative materials: From mechanistic insights to functional applications

Under the combined pressures of global carbon neutrality goals and climate change, the development of technologies with negative carbon potential is of critical importance. Biomass, as a renewable, carbon-neutral, and abundant resource, holds great potential for carbon sequestration. Hydrothermal carbonization (HTC) is a mild thermochemical conversion process well-suited for wet biomass, enabling the efficient synthesis of structurally tunable carbon materials. However, the HTC process involves complex reaction mechanisms and spans multiple disciplines, posing ongoing challenges in precisely controlling reaction pathways. This review summarizes recent advances in the HTC of biomass for the synthesis of negative carbon materials. It systematically discusses the underlying reaction mechanisms and structural regulation strategies of HTC, and highlights its emerging applications in energy, environmental remediation, catalysis, and soil improvement. The review aims to offer insights and guidance for the efficient synthesis of high-performance negative carbon materials. • Summarizes recent advances in hydrothermal carbonization of biomass. • Explores HTC reaction mechanisms and structural regulation strategies. • Highlights HTC-derived carbon applications in energy and environment. • Provides insights for efficient synthesis of carbon-negative materials.