Dickson D. Babu

The increasing global demand for energy and growing environmental concerns emphasize the crucial role of solar energy as a sustainable and nondepletable resource. Solar cells, particularly dye‐sensitized solar cells (DSSCs), have gained prominence due to their efficient conversion of solar power, ecofriendly manufacturing processes, and noteworthy stability. Current research in sustainable energy focuses on transitioning from metal‐based to metal‐free organic materials. Tandem solar cells, combining n‐type and p‐type semiconductors sensitized with diverse photoactive dyes, show potential to surpass thermodynamic limits in photon conversion efficiency. Notably, the exploration of n‐type DSSCs as photoanodes in tandem architectures is promising. However, the absence of efficient p‐type photoactive cathodes remains a significant obstacle. Global research efforts are dedicated to addressing charge recombination issues in NiO‐based devices to enhance the efficiency of p‐type DSSCs. The success of any DSSC hinges on the selection of dyes/sensitizers with suitable anchoring groups, wide absorption in the visible–NIR region, and a high extinction coefficient. This article comprehensively reviews advancements in developing highly efficient p‐type sensitizers, emphasizing their pivotal role in unlocking the full potential of tandem solar cells.

We present a study on a new class of Schiff bases with pyrimidine linked hydrazinyl azole backbone. These compounds were synthesized using conventional and ultrasonication methods. Our design strategy incorporated three heteroaromatic azoles and various substituents on the pyrimidine scaffold to enhance antimicrobial properties. Antibacterial and antifungal screenings were conducted against specific pathogens, and molecular docking studies supported the results. The compounds exhibited significant antimicrobial activities, particularly against K. pneumoniae , surpassing the standard drug. These Schiff bases hold promise as potential antimicrobial agents.

A new class of bis(azolyl) pyridine‐2,6‐dicarboxamides based derivatives were designed and synthesized by employing ultrasonication methodology. In this work, we studied the role of different heteroaromatic azole units such as oxazole, thiazole and imidazole moieties along with different donating/withdrawing substituents on the pyridine scaffold and anticipated to display good biological activities. The detailed molecular docking studies validates the antimicrobial activities of these targeted molecules. Further, to evaluate their antioxidant properties, the target compounds were exposed to three different invitro free radical scavenging assay methods. Further, using the disc diffusion method, the targeted molecules were screened for invitro antibacterial activities against the pathogenic stains. Besides, the targeted molecules were also tested against A. niger and P. chrysogenum strains to assess their antifungal activity. The screening results reveals that, the most of the compounds form the series demonstrating reasonable to decent antioxidant and antimicrobial activities against pathogenic stains in comparison with the standard drug.

Atomization of noble metals enable their electrocatalysis applications with low cost, whereas the isolated mononuclear site after atomization might lead leads to limited performance. Herein, we present a general strategy of atomically confined alloying (ACA) to synthesize an electrocatalyst of single atom iridium-trapping cobalt nanosheets with dual-reactive Ir–Co sites. The atomic Ir@Co nanosheets (1.7 wt% Ir) exhibit excellent oxygen evolution reaction (OER) performance with a small overpotential (273 mV at 10 mA cm⁻²) and high stability, higher than that of the Ir/C catalyst (290 mV at 10 mA cm⁻²). More importantly, density functional theory (DFT) calculations combined with experiments demonstrated that water oxidation proceeded on atomic Ir@Co nanosheets via a dinuclear tandem mechanism, in which Ir–Co dual sites cooperatively worked in favour of the sequential transfer from Co–OH* to Ir–O* via a Co–O–Ir intermediate, and stabilization of OOH* species by hydrogen bonding interaction. The cooperative mechanism based on a dinuclear electrocatalyst by ACA is hoped to open up more possibilities of single atom noble metal electrocatalysts for various applications.

Polymer electrolyte fuel cells (PEFCs) are among the most advanced energy technologies with low operating temperatures, high energy densities, ease of transportation and storage. However, the deficiencies such as low activity and high cost of the electrocatalysts at anodes greatly hinder their commercialization. The commonly used carbon black supports lack the capacity of regulation over the supported noble metals towards efficient electro‐catalytic oxidation of fuels. In this Mini‐Review, the prerequisite factors in advanced supports are outlined, ranging from self‐supported precious metal alloys as well as non‐noble metal materials, while simultaneously revealing the superiorities of some advanced supports beyond carbon black in terms of electronic conductivity, synergy with surface precious metals, chemical and electrochemical stability, and other possible interactions. The effects arisen from microscopic morphology, nano‐structure, and composition on the electrocatalytic activity/stability are also discussed. Finally, several of the most promising supports are highlighted, and the research trends of synergistic supports in future PEFCs are predicted.

Hydrogen production from water driven by electrochemical/solar energy is extremely desirable, but it requires a capable and robust electrocatalyst for the hydrogen evolution reaction (HER). For the aforesaid purpose, molybdenum carbide (Mo₂C) has been considered as an efficient electrocatalyst for hydrogen production; however, N‐Mo₂C has been less focused upon. For this purpose, we report a facile method for the synthesis of N‐Mo₂C active species. The as‐synthesized electrocatalyst exhibits a remarkable electrochemical performance for HER with a small onset potential of 30.6 mV vs. RHE and requires overpotential (η) of only 99.3 mV vs. RHE to render −10 mA cm⁻² current density. The Tafel slope of 62.8 mV dec⁻¹ further demonstrates the favorable reaction kinetics of the electrocatalyst. Moreover, for practical applications, solar‐driven hydrogen production has been efficiently implemented, which shows excellent faradaic efficiency (95.2 %) as well as solar‐to‐hydrogen generation efficiency (1.14 %). This facile approach for the synthesis of N‐Mo₂C active species can provide valuable enlightenment for the further development of photo‐/electrocatalysts.

Hydrogen generation from water splitting driven by electric/solar energy is highly desirable, which requires efficient and robust bifunctional electrocatalysts for both hydrogen and oxygen evolution reactions. 2D porous hybrids with attractive chemical and structural properties are the first‐class candidates for water splitting, while control over efficient and modulable synthesis remains a huge challenge. This work demonstrates a zeolitic imidazolate framework‐67 (ZIF‐67) nanoplate self‐template approach to fabricate 2D porous oxygen‐incorporated cobalt phosphide (CoPO) ultrathin nanosheets. The synthesis starts with the oriented growth of ZIF‐67 nanoplates along [211] crystal plane, followed by oxidation/phosphorization processes for pore generation and O/P coincorporation in the hybrid. The resultant 2D porous CoPO nanosheets afford very small voltages of 1.52 and 1.98 V for overall water splitting at 10 and 200 mA cm⁻², respectively. This excellent bifunctionality further provides the basis for photovoltage‐driven water splitting at a Faradaic efficiency of 97.6%. These findings offer a general strategy for rational design and modulation of 2D porous catalysts for various electrocatalytic and other applications.