Research Projects

The poor energy efficiency of electrochemical water splitting originates from the thermodynamically unfavourable and kinetically sluggish anodic water oxidation. A practical solution to this problem can be achieved by replacing anodic water oxidation with the thermodynamically favorable oxidation of benzylic substrates (benzylic alcohols, benzyl amines, tetrahydroisoquinolines, etc.) to produce value-added products. Although transition metal-based catalysts were demonstrated for the anodic oxidation of the benzylic substrates with high energy efficiency and conversion rate, most of these catalysts produced a low current density (~ 100 mA cm-2)-not suitable for industrial application. In contrast, noble metal-based catalysts, which can produce high current density, cannot find wide application because of their high-cost. In this context, this project will address the above-mentioned challenges by using metal-organic framework (MOF)-derived dual-atom catalysts (DACs) having formula: M1M2NxEy (where, M1 = transition metal, M2 = noble metal, and E = N/O/S/P). The DACs will ensure the minimum use of the noble metal (M2) with high atomic utilization. We have chosen MOF as the precursor of DAC because the metal nodes are atomically dispersed and stabilized by the coordination with the heteroatom of the bridging ligands in MOF and the pyrolysis of it produces DAC with isolated atomic sites. In addition, the pyrolysis of MOFs produces porous carbon or N-doped carbon which offer support for the uniform distribution of the atomic sites. Although single-atom catalysts have been demonstrated for the anodic oxidation of benzylic substrates and other organic compounds, DAC is never being used for the same purpose. In this project, we will explore DACs for the anodic oxidation of benzylic substrates to attain an industrial-scale current density (400 mA cm-2). To achieve this goal, we will design DACs consisting of noble metal and transition metal atomic sites. The ratio of noble metal to transition metal will be varied to attain improved activity, selectivity and stability of the catalyst. Control over the electronic properties of the DACs will be attained by tuning the coordinated neighbour atoms N and E (N/O/S/P) to achieve optimized activity and stability. Moreover, the coordination of the metallic sites with the heteroatoms (N, S, O, P, etc.) of heteroatom-doped carbon will stabilize the DAC. The asymmetrical charge distribution on two atomic sites having transition metal and noble metal will generate microenvironments to modulate the short- or medium-range interaction with each other. The metal-metal interaction will be tuned by direct interaction of the atomic sites or through bridging hetero atom(s). The synergistic interaction between the two metal centers facilitates the simultaneous adsorption of different reaction intermediates on two metal centers and a high selectivity will be achieved along with high catalytic activity.

Benzylic substrate oxidation, Value added product, Anodic oxidation, Dual atom catalyst, Industry scale current