Electrochemical CO₂ reduction to hydrocarbons using DFNT@MOF-Metal as a hybrid photoelectrocatalyst

The electrochemical reduction of CO₂ into value-added hydrocarbon fuels remains a grand challenge due to sluggish multielectron transfer kinetics and the limited stability of existing photocathodes. In this work, we report the design of a novel hybrid DFNT@MOF-Metal photoelectrocatalyst, in which transition metal based MOFs (Zn, Ni, Co, Mg) are uniformly anchored on dendritic fibrous nanotitania (DFNT). The hierarchical DFNT scaffold provides a three dimensional open-channel architecture with high surface area, ensuring homogeneous dispersion of MOF-metal nanodomains and facilitating efficient electron transport. The MOF-metal active sites, in turn, enable enhanced CO₂ adsorption, activation, and catalytic turnover through synergistic electronic interactions. Electrochemical tests under visible-light-assisted conditions revealed that DFNT@MOF-Metal catalysts exhibited significantly reduced charge transfer resistance and enhanced current density compared to pristine DFNT and MOF only references. Among the tested compositions, DFNT@MOF-Ni demonstrated the highest Faradaic efficiency and methane selectivity, while DFNT@MOF-Co, DFNT@MOF-Zn, and DFNT@MOF-Mg also showed improved performance over their single component counterparts. Kinetic analysis confirmed a pseudo first order reaction pathway for CO₂ to CH₄ conversion, and stability tests indicated negligible activity loss over ten consecutive electrochemical cycles. These findings establish DFNT@MOF-Metal hybrids as efficient, stable, and recyclable photoelectrocatalysts for selective CO₂ electroreduction, highlighting the critical role of DFNT morphology and multimetallic MOF centers in driving sustainable CO₂ to hydrocarbon energy conversion.