The adverse effect of fossil fuels on the environment is driving research to explore alternative energy sources. Research studies have demonstrated that renewables can offer a promising strategy to curb the problem, among which thermoelectric technology stands tall. However, the challenge with thermoelectric materials comes from the conflicting property of the Seebeck coefficient and the electrical conductivity resulting in a low power factor and hence a lower figure of merit. Researchers have reported various techniques to enhance the figure of merit, particularly in metal chalcogenide thermoelectric materials. Here we present a review on isovalent substitution as a tool to decouple the interdependency of the electrical conductivity and Seebeck coefficient to facilitate simultaneous enhancement in these two parameters. This is proven true in both cationic and anionic side substitutions in metal chalcogenide thermoelectric materials. Numerous publications relating to isovalent substitution in metal chalcogenide thermoelectric are reviewed. This will serve as a direction for current and future research to enhance thermoelectric performance and device application. This review substantiates the role of isovalent substitution in enhancing metal chalcogenide thermoelectric properties compared with conventional systems.

Designing highly efficient and low-cost electrocatalysts for oxygen evolution reaction is important for many renewable energy applications. In particular, strain engineering has been demonstrated as a powerful strategy to enhance the electrochemical performance of catalysts; however, the required complex catalyst preparation process restricts the implementation of strain engineering. Herein, we report a simple self-template method to prepare hierarchical porous Co₃O₄ nanowires (PNWs) with tunable compressive strain via thermal-oxidation-transformation of easily prepared oxalic acid-cobalt nitrate (Co(NO₃)₂) composite nanowires. Based on the complementary theoretical and experimental studies, the selection of proper solvents in the catalyst preparation is not only vital for the hierarchical structural evolution of Co₃O₄ but also for regulating their compressive surface strain. Because of the rich surface active sites and optimized electronic Co d band centers, the PNWs exhibit the excellent activity and stability for oxygen evolution reaction, delivering a low overpotential of 319 mV at 10 mA·cm^-2 in 1 M KOH with a mass loading 0.553 mg·cm^-2, which is even better than the noble metal catalyst of RuO₂. This work provides a cost-effective example of porous Co₃O₄ nanowire preparation as well as a promising method for modification of surface strain for the enhanced electrochemical performance.

Conversion of inert N₂ molecules into NH₃ via electrochemical methods is an environmentally friendly alternative to replace the traditional Haber-Bosch process. However, the development of highly efficient catalyst is still challenging. Herein, we report a density functional theory (DFT) based high-throughput screening to investigate the potential of 23 atomic transition metals (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, W, Pt and Au) supported on phosphorene monolayer as electrocatalyst for nitrogen reduction reaction (NRR). Our theoretical results demonstrate that V single atom anchoring on phosphorene monolayer exhibits good thermal stability, selectivity and excellent catalytic activity with a low overpotential of 0.18 V. Importantly, rational design principles and electronic descriptor between the intrinsic electronic properties and activation barrier have been developed. Our work offers a new promising noble metal-free catalyst for NRR and reveals profound insights into the activity origin to guide further design.