We summarize here recent advancements in Pt rare earth metal alloy and metal oxide catalysts for oxygen reduction and alcohol oxidation reactions.

Layered transition metal sulfides (TMS) are emerging as advanced materials for energy storage and conversion applications. In this work, we report a facile and cost-effective anion exchange technique to fabricate a layered, multifaceted, free standing, ultra-thin ternary cobalt molybdenum sulfide nanosheet (Co–Mo–S NS) architecture grown on a 3D porous Ni foam substrate. The unique Co–Mo layered double hydroxides are first synthesized as precursors and consequently transformed into ultra-thin Co–Mo–S NS. When employed as an electrode for supercapacitors, the Co–Mo–S NS delivered an ultra-high specific capacitance of 2343 F g⁻¹ at a current density of 1 mA cm⁻² with tremendous rate capability and extraordinary cycling performance (96.6% capacitance retention after 20 000 cycles). Furthermore, assembled Co–Mo–S/nitrogen doped graphene nanosheets (NGNS) in an asymmetric supercapacitor (ASC) device delivered an excellent energy density of 89.6 Wh kg⁻¹, an amazing power density of 20.07 kW kg⁻¹, and superior cycling performance (86.8% capacitance retention after 50 000 cycles). Such exceptional electrochemical performance of Co–Mo–S NS is ascribed to the good electrical contact with the 3D Ni foam, ultra-high contact area with the electrolyte, and enhanced architectural softening during the charging/discharging process. It is expected that the fabricated, unique, ultra-thin Co–Mo–S NS have great potential for future energy storage devices.

A porous, efficient, and durable nonprecious electrocatalyst for the oxygen reduction reaction (ORR) under both alkaline and acidic conditions is synthesized by a green, solvent-free, one-pot, economical, scalable, and template-free strategy. In situ formed graphitic carbon nitride (g-C₃N₄) is utilized as a sacrificial template for constructing the core–shell Fe₃C@NSC electrocatalyst with a highly porous substructure and nanosheet-like morphology. The presence of glucose facilitates the homogeneous distribution of nanoparticles and establishes the nanosheet structure, otherwise agglomeration and formation of nanotubes occur in the Fe₃C@NSC electrocatalyst. Optimizing the synthetic conditions generates a highly active ORR electrocatalyst with a unique mesoporous architecture, large surface area, high nitrogen doping level, encapsulated Fe₃C nanoparticles in NS co-doped carbon layers and multiple exposed edge active centers. The best performing electrocatalyst displays outstanding ORR performance under alkaline conditions with onset potential and half-wave potential (E_1/2) values of 1.059 and 0.938 V vs. the reversible hydrogen electrode (RHE), much higher than those of the state-of-the-art commercial Pt/C (20%), and admirable performance in acidic media. In addition, it exhibits 4e⁻ selectivity, tolerance toward methanol, and superb durability with zero degradation after 12 000 potential cycles under both alkaline and acidic conditions. These exceptional characteristics make the as-synthesized electrocatalyst one of the top-level non-precious ORR electrocatalysts reported to date.