Hori Pada Sarker

All Publications

• From Micro-environments to Macroscopic Effects: How the Alkaline Hydrogen Evolution Reaction Drives Cu Cathodic Corrosion ACS CATALYSIS Sarker, H., Goswami, A., Tang, M. T., Abild-Pedersen, F. 2025

  View details for DOI 10.1021/acscatal.4c07768

  View details for Web of Science ID 001484554300001

• Structural, Optoelectronic, Magnetic, and Photoelectrochemical Consequences of Copper Insertion into Alkaline Earth Metal (Mg, Ca, or Sr) Pyrovanadate Compound Frameworks. Inorganic chemistry Rawat, A., Danladi, F. I., Sarker, H. P., Zhang, C., Fulton, J., Ananth, R., Pereyra, A., Hadke, S. S., Kewalramani, S., Sangwan, V. K., Toth, P. S., Janáky, C., Bedzyk, M. J., Hersam, M. C., Meletis, E. I., Rajeshwar, K. 2025

  Abstract

  This study explores the manifold consequences of introducing copper into an alkaline earth metal (A = Mg, Ca, or Sr) pyrovanadate compound (A2V2O7) framework. Thus, powder X-ray diffraction coupled with Rietveld refinement showed that phase pure alloys, namely, Mg0.67Cu1.33V2O7, CaCuV2O7, and SrCuV2O7 could be obtained via solution combustion synthesis. Local structure distortions from copper insertion into the A2V2O7 compound framework were revealed by Raman spectroscopy and X-ray photoelectron spectroscopy. Importantly, the Cu2-xAxV2O7 alloy framework is shown below to be an excellent platform for demonstrating the complementarity of the two outcomes of bandgap photon absorption, namely, photovoltaic or photoelectrochemical (PEC) activity versus photoluminescence (PL). Thus, PL from the parent pyrovanadate was quenched when copper was introduced; concomitantly, PEC activity emerged for the semiconductor alloys. Changes in the electronic band structures on copper introduction were experimentally probed by diffuse reflectance spectroscopy and Kelvin probe measurements. These data were complemented by density functional theory (DFT) calculations. Finally, the magnetic attributes of the three alloys are discussed via both experiment and theory.

  View details for DOI 10.1021/acs.inorgchem.5c00280

  View details for PubMedID 40173268

• Prediction of Feasibility of Polaronic OER on the (110) Surface of Rutile TiO2. Chemphyschem : a European journal of chemical physics and physical chemistry Pada Sarker, H., Abild-Pedersen, F., Bajdich, M. 2024; 25 (11): e202400523

  Abstract

  The front cover artwork is provided by Dr. Hori Pada Sarker from Dr. Frank Abild-Pedersen's research group at the SLAC National Accelerator Laboratory. The image shows the generation of photoexcited carriers (electrons and holes) and the subsequent formation of hole polaron in rutile TiO2 during oxygen evolution reaction (OER). Read the full text of the Research Article at 10.1002/cphc.202400060.

  View details for DOI 10.1002/cphc.202400523

  View details for PubMedID 38837603

• Prediction of Feasibility of Polaronic OER on (110) Surface of Rutile TiO2. Chemphyschem : a European journal of chemical physics and physical chemistry Sarker, H. P., Abild-Pedersen, F., Bajdich, M. 2024: e202400060

  Abstract

  The polaronic effects at the atomic level hold paramount significance for advancing the efficacy of transition metal oxides in applications pertinent to renewable energy. The lattice-distortion mediated localization of photoexcited carriers in the form of polarons plays a pivotal role in the photocatalysis. By employing Hubbard-U corrected and hybrid density functional theory (DFT) methods, we systematically probe the polaronic effects in the catalysis of oxygen evolution reaction (OER) on the (110) surface of rutile TiO2 photocatalyst. Theoretical understanding of polarons within the surface, coupled with simulations of OER at distinct titanium (Ti) and oxygen (O) active sites, reveals diverse polaron formation energies with strong preference for bulk and surface bridge oxygen sites. Moreover, we provide the evidence for the facilitative role of polarons in OER. We find that hole polarons situated at subsurface, equatorial, and bridge site significantly reduce the Ti-active site OER overpotential by ~0.4 eV through the peroxo-oxygen pathway. We also observe that the presence of hole polarons stabilizes the *OH, *O, and *OOH intermediate species. Overall, this study provides a detailed mechanistic insight into polaron-mediated OER, offering a promising avenue for improving the catalytic activity of transition metal oxide-based photocatalysts.

  View details for DOI 10.1002/cphc.202400060

  View details for PubMedID 38427793