Recent Advances in Transition Metal Phosphide Nanocatalysts for H₂ Evolution and CO₂ Reduction

Green hydrogen energy has captivated researchers and is regarded as a feasible option for future energy-related aspirations. The emerging awareness of renewable energy-driven hydrogen generation and carbon dioxide reduction calls for the use of unconventional schematic tools in the fabrication of nanocatalyst systems. Transition metal phosphides are state-of-art, cost-effective, noble-metal-free materials that have been comprehensively examined for sustainable energy-driven applications. Recent reports on these advanced functional materials have cemented their candidature as high-performance catalytic systems for hydrogen production and for carbon dioxide conversion into value-added chemical feedstock. Bimetallic NiCoP (238.2 mmol g⁻¹ h⁻¹) exhibits top-notch catalytic competence toward photocatalytic HER that reveals the energy-driven application of a pristine class of TMPs, whereas heterostructured Ni₂P/CdS was found to be fit for photochemical CO₂ reduction, as well as for HER. On the other hand, pristine Ni₂P was recently ascertained as an efficient electrocatalytic system for HER and CO₂RR applications. A wide array of physicochemical modulations, such as compositional and structural engineering, defect generation, and facet control, have been used for improving the catalytic efficiency of transition metal phosphide nanostructures. In this review, we succinctly discuss the proficiency of transition metal phosphides in green hydrogen production and carbon dioxide conversion via photochemical and electrochemical pathways. We detail the significance of their structural properties and brief the readers about the synthetic advancements without deviating from our goal of summarizing the recent achievements in energy-driven applications.