(4ft) Theoretical Insights into Alternative Oxygen Evolution Reactions

The sun is the earth’s most abundant energy resource. One of the largest challenges facing the world today is how to harness the sun’s energy to generate energy-rich fuels for a sustainable future. Inspired by plant photosynthesis, scientists are designing materials and chemical processes that can convert sunlight into chemical energy using only components of air: water, carbon dioxide, and nitrogen—known as artificial photosynthesis. Directly producing liquid fuels from these abundant feedstocks would provide an efficient way to store and dispatch solar energy, paving the way to energy independence. The aim is to develop the fundamental scientific principles by which durable coupled microenvironments can be co-designed to efficiently and selectively generate liquid fuels from sunlight, water, carbon dioxide, and nitrogen.

Doctoral Research

My Ph.D. research in the Department of Physics at the Indian Institute of Technology Delhi (IIT Delhi, India) utilized theoretical /experimental methods to determine self-energy and excitonic effects in wide band gap energy materials. Many-body perturbation theory was employed to investigate the complexities of defects present in semiconductors, particularly metal-oxides and perovskites. Further optical, excitonic, and polaronic properties were computed using physics-based models. These studies are deemed crucial for the development and advancement of renewable energy technologies, as well as for their applications in photocatalytic and electrocatalytic water splitting and solar cells.

Postdoctoral Research

As a Postdoctoral Researcher at Stanford University, I investigate the Cu-oxidation and its roles in unassisted CO₂ Reduction and electrochemical oxygen evolution reaction using first principles calculations. Sunlight-driven photocatalytic CO₂ reduction to CO under unassisted (unbiased) conditions has been demonstrated recently using heterostructured catalysts that combine p-type GaN with plasmonic Au nanoparticles and Cu nanoparticle co-catalysts (p-GaN/Al₂O₃/Au/Cu) [1]. However, the exact oxidation state of Cu and the directionality of hole transfer between Au and Cu remain under debate. Efforts are made here to investigate the different oxidation states of Cu under unassisted photocatalytic operating conditions in collaboration with experimental colleagues, who found that the Cu nanoparticles are primarily composed of Cu₂O and CuO, CuCO₃.Cu(OH)₂ species, with no detectable metallic Cu present. The high stability of CuCO₃.Cu(OH)₂ is confirmed by calculated bulk thermodynamics, which is consistent with its largest contribution in the Pourbaix diagram, as observed experimentally (Figure a). Insights into the origin of charge transfer are gained through simulations of material interfaces, namely Au/CuO, Au/Cu₂O, and Au/CuCO₃.Cu(OH)₂, supporting the experimentally observed light-driven hole transfer from Au to Cu [2].

In addition, I also work on Cu⁺³ oxidation state relevant for OER. Notably, significant progress has recently been made in understanding the behavior of copper oxide (CuO) under oxidizing electrochemical conditions (> 1.5 V) [3]. My studies show CuO transforms into the OER active phase CuOOH, as evidenced by the bulk Pourbaix diagram (Figure b), and also reveal a novel square planar, non-magnetic CuOOH phase, supported by calculated Raman spectroscopic analysis. These findings provide insights into the electrochemical properties of copper oxide phases and their relevance to electrocatalytic OER.

During my tenure as a postdoctoral research scholar at CNRS lab, France, for two years, a computational methodology developed by our group at Rennes was utilized. The intimate connection between surface and interface dipoles and work functions or valence band alignments was highlighted [4]. The energy level alignments of halide perovskites were inspected, considering (i) the effect of surface termination and the ability to fine-tune and interpret the shift in energy alignments via (ii) surface coating and (iii) surface functionalization and/or passivation with molecules [5]. The importance of local strain relaxation at the surfaces or interfaces was emphasized, and classical approaches based on capacitor models were revisited (Figure c). Furthermore, the additive nature of surface dipoles in heterostructures was illustrated through a 2D/3D perovskite interface. This methodology provides a practical tool for interpreting band alignments in complex perovskite-based heterostructures and buried interfaces [6]. The scope of this work extends beyond halide perovskites, facilitating the integration of results from atomistic ab initio calculations and classical simulation approaches for multilayered thin film devices.

Research Vision

The vision of the Pooja Basera Lab is to explore alternative OER reactions that exhibit high efficiency and lower overpotentials. Notably, current tandem systems use water oxidation as the anodic reaction, demanding high photoelectrode voltage. It’s essential to find alternative anodic reactions to lower voltage needs, boost current density, and yield alternative valuable molecular products. My strategy involves applying concepts from thermal and homogeneous catalysis into electro and heterogeneous catalysis, and constructing a volcano plot to identify the suitable window for ketone/oxo and epoxy/peroxo reactions versus OER, guiding experiments towards efficient catalysts for anodic reactions (Figure d). Additionally, the proposal includes utilizing the 2e- oxidation of H₂O to H₂O₂ as an alternative oxidative fuel. Overpotentials for this process are slightly higher than for OER (>1.7 V vs RHE), with the H₂O₂ product offering added value. Stable oxides such as TiO₂, SnO₂, and conducting supports like ITO and ATO on Au, Pt are suitable for this reaction and can serve as photoanodes simultaneously. We will also collaborate with experimental groups specializing in alternative anodic reactions to verify the hypothesis predicted by theoretical model. The combined theoretical and experimental results aim to develop fundamental insights into the selectivity between epoxides, ketones, and aldehydes from olefin oxidation reactions, facilitating the construction of a library of diverse and selective anodic electrocatalysts.

Teaching Interests

I am willing to teach the core subjects related to Computational material science such as Solid State Physics, Electrodynamics, Quantum Mechanics, Mathematical Physics, Electrocatalysis, Photocatalysis, Quantum materials with focus on defects in semiconductors, Optical properties, 2D materials heterostructures, excitonic and polaronic properties, and thermodynamic courses. Additionally, considering my experience as a teaching assistant at IIT Delhi during my Ph.D. degree, I would like to introduce course Computational Materials Modelling for heterogeneous catalysis. I also took a few regular classes as TA and taught courses such as Computational condensed matter physics, including density functional theory (DFT) and beyond approaches, during my Ph.D. For these courses, I delivered a few regular lectures and tutorials every semester and helped the instructors to prepare test question papers, prepared sample answers for homework and tests, proctored mid-term and final tests, and graded the tests. Additionally, apart from these regular classes, I used to conduct several doubt clearing sessions with the students.

Mentorship and DEI

I am a core team member of the LiSA Sunrise Leadership Networks and DEI initiatives within LiSA (Liquid Sunlight Alliance https://www.liquidsunlightalliance.org/). LiSA is an Energy Innovation Hub devoted to advancing the science of liquid solar fuels. We are a diverse team of more than 100 scientists spanning seven institutions (Caltech, LBNL, NREL, SLAC etc.) with backgrounds in chemistry, physics, materials science, and chemical and electrical engineering, all working together to directly generate liquid fuels from sunlight, water, carbon dioxide and nitrogen. More information about the Sunrise Network at https://www.liquidsunlightalliance.org/sunrise-network. During my Ph.D., I mentored two M.Tech students under the direct supervision of my advisor for their master’s thesis. Additionally, I served as a teaching assistant in B.Tech PYL 100, Electronics Lab from 2016-2019 at IIT Delhi.