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AuCo alloys were prepared by magnetron sputtering for the first time without considering the insolubility on the phase diagram. The electronic effect between Au and Co can change the oxygen adsorption energy and the ORR activity. The ORR activity of the Au46Co54 alloy electrode not only exceeded that of Au, but also exceeded that of Pt in basic solution. [ABSTRACT FROM AUTHOR]

Exploring the mechanism of hydrogen oxidation reaction (HOR) in alkaline media is essential for the development of alkaline polymer electrolyte fuel cells (APEFCs). In this work, a series of Pd−Ni(OH)2 composites with different Pd/Ni atomic ratios (Pd : Ni=1:0 (without Ni addition), 7 : 1, 5 : 1, 3 : 1, 1 : 1) have been synthesized via wet chemical reduction method, and their corresponding HOR activities have been systematically evaluated with rotating disk electrode (RDE) technique. A good linear relationship between the HOR activities (described as the mass activity and exchange current density) and the surface oxophilicities (assessed by the oxidation current at 0.3 V vs. RHE in CO stripping voltammetry) is observed, indicating a bifunctional mechanism for HOR. The present study offers a direction for further improving the activity of Pd‐based HOR electrocatalyst. [ABSTRACT FROM AUTHOR]

Core–shell structured catalysts have been widely investigated for fuel cell applications in the recent decade. The skin-substrate interaction has provided a well tunable basis for the design of better catalysts. Herein, we report an implementation of fabricating a Pd skin onto the AuCu intermetallic nanoparticles (denoted as Pd S AuCu i NPs), and its exceptionally high activity towards the oxygen reduction reaction (ORR) in alkaline media. The structure of Pd S AuCu i NPs was well characterized through combining a variety of techniques, including high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and energy dispersive X-ray (EDX) line scanning analysis, synchrotron X-ray diffraction patterns (SXRD), X-ray photoelectron spectra (XPS), X-ray fluorescence analysis (XRF), and electrochemical measurements. The AuCu intermetallic core was identified to be fully wrapped by a Pd skin with 2–3 atomic layers. The catalytic activity of Pd S AuCu i NPs towards the ORR in alkaline is more than 8-times higher in surface-specific activity (SA), and 20-times higher in mass-specific activity (MA), than that of the commercial Pt/C catalyst, and remains reasonably stable in thousands cycles of potential sweep. Such an outstanding performance is attributed to the reduction in the oxygen affinity of the Pd skin caused by a proper and stable shrink in Pd lattice induced by the AuCu intermetallic substrate. [ABSTRACT FROM AUTHOR]

N,S,Fe-doped graphene nanosheets were directly synthesized from aminothiazole, a precursor molecule that contains N and S atoms, through Fe catalysis under heat treatment. The graphene nanosheets exhibited high electrocatalytic activity toward oxygen reduction reaction in both acidic and alkaline media during rotating disk electrode half-cell and fuel cell tests. [ABSTRACT FROM AUTHOR]

A family of cheap carbon black based Fe–Nx/C electrocatalysts with superhigh-performance for oxygen reduction reaction (ORR) were synthesized. The one with Fe 10 wt% and N 1.57 wt% shows the best performance. The activity order of different active sites for ORR was revealed firstly: Fe–N4/2–C ＞ Fe4–N–C ＞ N–C > Fe4–C ≈ C. [ABSTRACT FROM AUTHOR]

Combined computational and experimental studies reveal a noble, non-d-band effect on Ag activation and electrocatalysis: upon coating Ag onto the even more inert Au surface, the catalytic activity toward the oxygen reduction reaction in alkaline media can be improved by about half an order of magnitude in comparison to the usual Ag surface. [ABSTRACT FROM AUTHOR]

Graphical abstract A new type of low-cost FeNx/C catalyst for oxygen reduction reaction (ORR) is prepared based on pretreatment of carbon and iron with a simple acid refluxing step. The catalyst shows high ORR performance in both alkaline and acid media, making it one of the most promising alternatives to Pt-based ones for ORR in fuel cells. Abstract We demonstrate a new and simple method for pre-treating the carbon material and iron precursor to prepare oxygen reduction reaction (ORR) catalysts, which can produce super-high performance and stability in alkaline solution, with high performance in acid solution. This strategy using cheap materials is simply controllable. Moreover, it has achieved smaller uniform nanoparticles to exhibit high stability, and the synergetic effect of Fe and N offered much higher performance in ORR than commercial Pt/C, with high maximum power density in alkaline and acid fuel cell test. So it can make this kind of catalysts be the most promising alternatives of Pt-based catalysts with best performance/price. [ABSTRACT FROM AUTHOR]

Completely precious metal-free alkaline polymer electrolyte fuel cells (APEFCs) are hindered by the lack of active non-precious metal hydrogen oxidation reaction (HOR) catalysts. Up to now, few studies have focused on the APEFC performance of non-precious metal HOR catalysts. Herein, upon simply adjusting the H 2 /Ar ratio during calcination, we synthesized a Ni-core carbon-shell (Ni@C) catalyst that exhibits an electrochemical surface area (ECSA)-normalized exchange current density of 0.090 mA cm−2, the highest among reported Ni-based HOR catalysts. More importantly, APEFC with the optimized catalyst, Ni-1% H 2 /Ar as anode catalyst, has achieved a peak power density of 670 mW cm−2 (H 2 –O 2) and 546 mW cm−2 (H 2 -Air CO 2 -free), higher than the state-of-the-art APEFC with Ni-based HOR catalysts, and can to stably work for 100 h at 200 mA cm−2. Characterization results show that H 2 is able to affect the particle size and etch the carbon shell of the catalysts during synthesis, which can boost the apparent HOR catalytic activity. Further experiments reveal that proper H 2 concentration during synthesis can lower the hydrogen binding energy (HBE), resulting in the enhanced intrinsic HOR catalytic activity of Ni-1% H 2 /Ar. • Ni@C catalyst exhibits a high intrinsic HOR catalytic activity of 0.090 mA cm−2. • The high HOR catalytic activity is derived from a H 2 -etched effect on carbon shell. • In APEFC test, Ni-1% H 2 /Ar reaches a PPD of 670 mW cm−2 (H 2 –O 2). • The APEFC is durable of 100 h at 200 mA cm−2. [ABSTRACT FROM AUTHOR]

A sustainable Iron (Fe), Nitrogen (N) co-doped high performance Fe–N x /C electrocatalyst for oxygen reduction reaction (ORR) is synthesized simply based on nitric acid oxidation of cheap carbon black. The obtained optimal nonprecious metal electrocatalyst shows high ORR performance in both alkaline and acidic conditions and possesses appreciable performance/price ratio due to its low cost. Furthermore, the structure-activity relationship of different active sites on Fe–N x /C is revealed systematically: Fe–N 4/2 –C > Fe 4 –N–C > N–C >> Fe 4 –C ≥ C, from both experimental and theoretical points of view. [ABSTRACT FROM AUTHOR]

Co–Mn oxides are a group of highly effective non-precious metal oxygen reduction reaction (ORR) catalysts for alkaline polymer electrolyte fuel cells (APEFCs). Despite being widely studied in alkaline solutions, limited studies of them have been developed in APEFCs. In this work, we evaluate the performance of a rock-salt-type Co–Mn composite oxides (CoMnO 2 /C) in both alkaline solution and APEFCs. Other than that, we also test its durability in APEFCs and investigate its degradation mechanism. CoMnO 2 /C exhibits a high ORR activity in both rotate disk electrode (RDE) study and APEFCs test. The ORR half-wave potential is 0.86 V in 1 M KOH, and the peak power density (PPD) reaches 1.2 W/cm2 in H 2 –O 2 APEFCs when using PtRu as anode. In air (CO 2 -free) condition, APEFC reaches a PPD of 0.83 W/cm2, and can operate over 40 h at a constant current density of 200 mA/cm2. Further experiments reveal that the cell performance degradation can be ascribed to the dissolution and valence increase of Mn from +3 to +3.6 on the catalysts surface. • CoMnO 2 /C exhibits high performance in both alkaline solution and APEFCs. • In air (CO 2 -free) condition, CoMnO 2 /C reaches a PPD of 0.83 W/cm2. • APEFCs using CoMnO 2 /C cathode can operate over 40 h at 200 mA/cm2. • Cell performance degradation is due to the dissolution and valence increase of Mn. [ABSTRACT FROM AUTHOR]