Pt electrocatalysts with high activity and durability have still crucial issues for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). In this study, a novel catalyst consisting of Pt nanoparticles (NPs) on TiO x /C composites (TiO x -V o -H/C) with abundant oxygen vacancies (V o ) is proposed, which is abbreviated as PTO-V o -H/C. The introduction of V o helps anchor highly dispersed Pt NPs with low loading and strengthen the strong metal−support interaction (SMSI), which benefits to the enhanced ORR catalytic activity. Moreover, the accelerated durability test (ADT) demonstrates the higher retention of ORR activity for PTO-V o -H/C. Experimental and theoretical analyses reveal that electronic interactions between Pt NPs and TiO x /C composite support give rise to an electron-rich Pt NPs and strong SMSI effect, which is favorable for the electron transfer and stabilization of Pt NPs. More importantly, the assembled PEMFC with PTO-V o -H/C shows only 6.9% of decay on maximum power density after 3000 ADT cycles while the performance of Pt/C sharply decreased. This work provides a new insight into the unique vacancy regulation of dispersive Pt on metal oxides for superior ORR performance.

A sulfonated poly(ether ether ketone) (SPEEK) proton exchange membrane with side-chain grafted sulfamic acid (SA) was designed. The introduction of SA with an amphoteric functional group achieves the purpose of preventing the migration of vanadium ions in the case of a lossless proton conductive group (−SO3H), which is caused by the Donnan repulsion of a protonated −NH– group to a vanadium ion. At the same time, acid–base pairs and hydrogen bonds are formed between the sulfonated side-chain grafted secondary amine (−NH−) group and the sulfonic (−SO3H) group, which hinders the penetration of vanadium ions. The results show that the prepared SPEEK-SA-50 membrane has high proton conductivity (0.099 S cm–1) and vanadium ion selectivity (1.8 × 105 S min cm–3), and its selectivity is significantly improved compared with SPEEK (4.9 × 104 S min cm–3) and the Nafion 212 membrane (4.8 × 104 S min cm–3). Under the condition of 80 mA cm–2, the Coulombic efficiency (CE) of the vanadium redox flow battery with the SPEEK-SA-50 membrane is 95.45%, and the energy efficiency (EE) is 76.11%, which is better than that of the Nafion 212 membrane (CE: 86.39%; EE: 68.26%).

The development of nanocomposites with unique structures by combining perovskites (ABO 3 ) is of significant importance for improving oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The introduction of transition metals in active B sites is considered a useful pathway to regulate the chemical and electronic properties of perovskites. In this study, a bifunctional activity-enhanced La(Ni 0.1 )MnO 3 perovskite decorated with N-doped carbon (NC) is developed by a B-site doping strategy. The resulting La(Ni 0.1 )MnO 3 @NC catalyst possesses numerous benefits including unique morphology, controllable synthesis, high conductivity, bifunctional activity, and durability. The enhancement was attributed to the synergistic effect of Ndoped porous carbon and [MnO 6 ] with the incorporation of [NiO 6 ], resulting in the regulated charge redistribution and disorder degree. Remarkably, the rechargeable Zn−air battery assembled with La(Ni 0.1 )MnO 3 @NC in the air cathode also displays satisfactory performance due to the regulation of coordination units when compared with a commercial catalyst. This study shows that the catalytic performance of perovskite oxide-based electrocatalysts can be significantly improved by B-site regulation and allows for the construction of effective cathode catalysts for metal−air batteries.

As ideal cathode catalysts for proton exchange membrane fuel cells (PEMFCs), the oxygen reduction reaction (ORR) activity and durability of Pt‐based alloys can be improved further. This study presents the catalyst with Au doping on the surface of an ordered PtFe alloy (Au‐PtFe/C) utilizing a synergistic process of microwave reduction and chemical replacement, as well as the reorganization of a Pt‐rich surface using acid etching and high temperature annealing. Physical characterization indicated that the oxygen binding energy on the surface of Au‐PtFe/C was more effective at promoting the ORR reaction than commercial Pt/C, which contributes significantly to its enhanced activity. Further electrochemical tests revealed that the Au‐PtFe/C catalyst exposes abundant active sites for ORR, with mass and specific activity up to 12 and 8 times that of commercial Pt/C, respectively. Additionally, the catalyst demonstrated remarkable durability following 10,000 cycles of accelerated durability tests (ADT) in acidic circumstances. In PEMFC test, the single cell with an Au‐PtFe/C cathode also performed admirably when compared with commercial Pt/C. Owing to its facile synthesis, low cost, and exceptional performance, this bimetal‐doped ordered Pt‐based alloy has the capability to be a promising component in fuel cells commercialization.

A general method for the direct synthesis of highly homogeneous and dense polymerized carbon nitride (PCN) nanosheet films on F: SnO2 (FTO) is developed. Detailed photoelectrochemical (PEC) water‐splitting studies reveal that the as‐synthesized PCN films exhibit outstanding performance as photoanode for PEC water‐splitting. The optimal PCN photoanode exhibits excellent photocurrent density of 650 µA cm−2, and monochromatic incident photon‐to‐electron conversion efficiency (IPCE) value up to 30.55% (λ = 400 nm) and 25.97% (λ = 420 nm) at 1.23 VRHE in 0.1 m KOH electrolyte. More importantly, the PCN photoanode has an excellent hole extraction efficiency of up to 70 ± 3% due to the abundance of active sites provided by the PCN photoanode nanosheet, which promotes the transport rates of OER‐relevant species. These PCN films provide a new benchmark for PCN photoanode materials.