Research Projects

This proposal aims to explore the synthesis of single-atom catalysts (SACs) for electrocatalytic, photocatalytic, and photoelectrocatalytic H₂ generation via overall water splitting. The overall water splitting requires an electrolyzer, involving the cathode and anode electrodes. The cathode and anode electrodes require suitable hydrogen and oxygen evolution reaction (HER and OER) catalysts, respectively. The benchmark or standard catalysts for HER and OER are Pt and Ru/Ir-oxide, respectively. The low abundance and high cost of these catalysts deter those from large-scale applications. Thus, the strategies to reduce the use of noble-metal catalysts include their size reduction, forming alloys, and using suitable support, which all deliver improved catalytic performance. To go beyond reducing the catalyst’s particle size is to prepare SACs on suitable supports. SACs are the materials that possess uniformly distributed single atoms on a suitable support, where the isolated single atoms act as the catalytic sites. It is noted that the support and its interaction with the single atom play a significant role. Recently, there has been a huge research interest in SACs because of not only the minimization of the catalyst amount but also exceptionally high catalytic activity due to the large surface area of catalytic sites and drastic changes in their physical and chemical properties, such as conductivity, band structure, and charge distribution. As of now, the research on SACs has primarily focused on Pt on different supports for its application in electrocatalytic HER. For example, Zhang et al. reported a two-step process in preparing the Pt SAC and demonstrated 32 times higher performance of H₂ oxidation reaction than that of the commercial Pt/C catalyst [Zhang et al., Symmetry Evolution Induced 2D Pt Single Atom Catalyst with High Density for Alkaline H₂ Oxidation. Adv. Mater. 2024, 36, 2404672]. There are reports on other noble metal-based SACs for different catalytic applications. The main challenges of SACs include the aggregation of atoms and the mobility of atoms under the given catalyst’s application. Thus, we propose that bimetallic and/or trimetallic single atoms could address the drawback of aggregation via proximity interactions of two different atoms that could induce a synergistic effect. Our group has demonstrated the synthesis of bi- and trimetallic alloy nanoparticles of size less than 5 nm on carbonaceous supports as catalysts with an improved catalytic performance [Monodispersed PtPdNi Trimetallic Nanoparticles-Integrated RGO Hybrid Platform for Direct Alcohol Fuel Cell. ACS Sustainable Chem. Eng. 2018, 6, 7769 and Bimetallic PtAu Alloy Nanoparticles-Integrated g‑C₃N₄ Hybrid as an Efficient Photocatalyst for Water-to-Hydrogen Conversion. ACS Appl. Mater. Interfaces 2019, 11, 478]. However, we could not demonstrate the SACs due to the unavailability of the main characterization techniques. The research on SACs is very new, having been around for about a decade, and there is very limited research in India. The main limitation is the need for sophisticated state-of-the-art techniques (HAADF-STEM and EXAFS) to characterize them. Recently, we have a start-of-the-art double-corrected 300 kV HRTEM with an EELS detector at IIT KGP. Thus, we could make quick progress on this contemporary research. Moreover, there are limited studies on SACs on photocatalytic and photoelectrocatalytic H₂ generation. So, we intend to synthesize SACs with different semiconductor supports to achieve high H₂ generation performance. In particular, we expected to achieve the overall water-splitting at less than 1.5 V and 1.0 V at 10 mA/cm² in a two-electrode electrolyzer using alkaline electrolyte and with small-molecule-assisted oxidation, respectively. In case of photocatalytic and photoelectrocatalytic H₂ generation, we are expecting the apparent quantum yield of 20-30% or more, for practical application.