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Bimetallic nanoparticles have attracted increasing scientific and technological interest as modules for creating nanoscale materials with unique magnetic, electronic, and chemical properties. The properties of bimetallic NPs are functions of... 

Photoactive single-atom catalysts (SACs) are among the most exciting catalytic materials for solar fuel production. Different SACs, including our own Co SACs, have been prepared on graphitic carbon nitride (C3N4) for use in photocatalysis. Building on our prior success, we report here doped C3N4 using various supplemental carbon dopants as the support for Co SACs. The Co SAC on a dianhydride doped C3N4 showed the highest activity in photocatalytic CO2 reduction. Catalyst characterization was carried out to explore the origin of the enhanced activity of this particular Co SAC. The dianhydride doped C3N4 possesses unique microstructural features, including large inter-layer space and fibrous morphology, that could contribute to the enhanced photocatalytic activity. Our results further indicate that the dianhydride is the most effective dopant to incorporate aromatic moieties in C3N4, which resulted in improved charge separation and enhanced activity in photocatalysis. 

Current synthesis techniques for metal oxide (MOx)-supported catalysts have certain limitations of undesired target loading, ineffective dispersion of active species over the surface, uncontrolled particle size of active species, and complicated synthesis steps. We developed a one-pot chemical vapor deposition (OP-CVD) methodology; by using which a solid metal precursor forms a vapor in a controlled condition and gets supported over the surrounding matrix. The theoretical stability followed by experimental validation using TGA is crucial for selecting the metal precursors. Three simple steps viz. premixing, dispersion, and rapid fixation by calcination are involved in the catalyst development via the OP-CVD approach. This study solely focused on the synthesis of 3d transition MOx over ceria support. The physicochemical characterizations of the prepared catalysts were performed by XRD, ICP-OES, SEM-EDX, CO pulse chemisorption, XANES, and EXAFS analyses to understand the crystal structure of involved species, target metal loading, dispersion, and particle size and prove the feasibility and viability of OP-CVD. The prepared catalysts were further tested for reverse water gas shift (RWGS) reaction to link their structural information with activity. The RWGS reaction data showed that the CO activity and CO selectivity were metal - and metal precursor-dependent. Higher CO activity of > 0.1 mol/h g-cat was observed for Cu and Co-based catalysts, with CO selectivity of ~100 %. This study provides an opportunity to produce effcient supported catalysts in a convenient way, providing effective catalytic activity.