Search

Abstract Anion exchange membrane fuel cells (AEMFCs) are one of the ideal energy conversion devices. However, platinum (Pt), as the benchmark catalyst for the hydrogen oxidation reaction (HOR) of AEMFCs anodes, still faces issues of insufficient performance and susceptibility to CO poisoning. Here, we report the Joule heating-assisted synthesis of a small sized Ru1Pt single-atom alloy catalyst loaded on nitrogen-doped carbon modified with single W atoms (s-Ru1Pt@W1/NC), in which the near-range single Ru atoms on the Ru1Pt nanoparticles and the long-range single W atoms on the support simultaneously modulate the electronic structure of the active Pt-site, enhancing alkaline HOR performance of s-Ru1Pt@W1/NC. The mass activity of s-Ru1Pt@W1/NC is 7.54 A mgPt+Ru -1 and exhibits notable stability in 1000 ppm CO/H2-saturated electrolyte. Surprisingly, it can operate stably in H2-saturated electrolyte for 1000 h with only 24.60 % decay. Theoretical calculations demonstrate that the proximal single Ru atoms and the remote single W atoms synergistically optimize the electronic structure of the active Pt-site, improving the HOR activity and CO tolerance of the catalyst.

Abstract The generation of green hydrogen by water splitting is identified as a key strategic energy technology, and proton exchange membrane water electrolysis (PEMWE) is one of the desirable technologies for converting renewable energy sources into hydrogen. However, the harsh anode environment of PEMWE and the oxygen evolution reaction (OER) involving four‐electron transfer result in a large overpotential, which limits the overall efficiency of hydrogen production, and thus efficient electrocatalysts are needed to overcome the high overpotential and slow kinetic process. In recent years, noble metal‐based electrocatalysts (e.g., Ru/Ir‐based metal/oxide electrocatalysts) have received much attention due to their unique catalytic properties, and have already become the dominant electrocatalysts for the acidic OER process and are applied in commercial PEMWE devices. However, these noble metal‐based electrocatalysts still face the thorny problem of conflicting performance and cost. In this review, first, noble metal Ru/Ir‐based OER electrocatalysts are briefly classified according to their forms of existence, and the OER catalytic mechanisms are outlined. Then, the focus is on summarizing the improvement strategies of Ru/Ir‐based OER electrocatalysts with respect to their activity and stability over recent years. Finally, the challenges and development prospects of noble metal‐based OER electrocatalysts are discussed.

Noble metals play a momentous role in heterogeneous catalysis but still face a huge challenge in selectivity control. Herein, the authors demonstrate that isolating contiguous Pt atoms and forming Pt-Zn intermetallic nanoparticles is an effective strategy to optimize the selectivity of Pt catalysts.

Single-site catalysts supported by ultrathin two-dimensional (2D) porous matrix are desirable for catalytic reactions, yet their synthesis remains a great challenge. Herein the authors report a cocoon silk chemistry strategy to synthesize isolated metal single-site catalysts embedded in ultrathin 2D porous N-doped carbon nanosheets.

The search for a low-cost, ultrastable, and highly efficient non-precious metal catalyst substitute for Pt in the oxygen reduction reaction (ORR) is extremely urgent, especially in acidic media. Herein, we develop a template-assisted pyrolysis (TAP) method to obtain a unique Co catalyst with isolated single atomic sites anchored on hollow N-doped carbon spheres (ISAS-Co/ HNCS). Both the single sites and the hollow substrate endow the catalyst with excellent ORR performance. The half-wave potential in acidic media approaches that of Pt/ C. Experiments and density functional theory have verified that isolated Co sites are the source for the high ORR activity because they significantly increase the hydrogenation of OH* species. This TAP method is also demonstrated to be effective in preparing a series of ISASM/ HNCS, which provides opportunities for discovering new catalysts. [ABSTRACT FROM AUTHOR]