Nano enzyme catalysts for sustainable transformation of carbon-centred chemicals

Nano enzyme catalysts are an emerging class of heterogeneous catalysts that translate enzymatic concepts such as site isolation, cooperative motifs, second-sphere interactions and microenvironment regulation into robust solids for the selective transformation of carbon-centred molecules under practical conditions. This review defines nano enzyme catalysts and distinguishes them from biomedical nanozymes, then summarises design principles that link atomic-scale active site construction and microenvironment engineering to reaction pathway control in carbon conversion. Mechanistic descriptors from enzymology and surface catalysis are compared to clarify when Michaelis-Menten type saturation behaviour reflects an enzyme-like catalytic cycle and when it more likely originates from adsorption or surface coverage limitations. Key strategies are discussed in the context of stabilising critical intermediates while suppressing deep oxidation, overhydrogenation and coke formation. These strategies include single-atom sites and sub-nanoclusters, defect and vacancy anchoring, confinement within porous frameworks and regulation of local hydrophilicity or hydrophobicity together with proton and electron transfer. Synthesis routes and representative thermal catalytic case studies are reviewed, followed by remaining challenges in operando active site identification, quantitative microenvironment descriptors, scalable synthesis and long-term stability. • Defines nano enzyme catalysts for carbon-centred heterogeneous catalysis. • Links site isolation and coordination to selectivity in carbon conversion. • Shows how microenvironments tune intermediates and suppress side reactions. • Summarises scalable synthesis and precise site engineering for nano enzyme catalyst.