For the large-scale sustainable implementation of polymer electrolyte membrane fuel cells in vehicles, high-performance electrocatalysts with low platinum consumption are desirable for use as cathode material during the oxygen reduction reaction in fuel cells. Here we report a carbon black-supported cost-effective, efficient and durable platinum single-atom electrocatalyst with carbon monoxide/methanol tolerance for the cathodic oxygen reduction reaction. The acidic single-cell with such a catalyst as cathode delivers high performance, with power density up to 680 mW cm−2 at 80 °C with a low platinum loading of 0.09 mgPt cm−2, corresponding to a platinum utilization of 0.13 gPt kW−1 in the fuel cell. Good fuel cell durability is also observed. Theoretical calculations reveal that the main effective sites on such platinum single-atom electrocatalysts are single-pyridinic-nitrogen-atom-anchored single-platinum-atom centres, which are tolerant to carbon monoxide/methanol, but highly active for the oxygen reduction reaction.

A notable trend in OER activity on transition metal phosphide pre-catalysts is reported. Remarkably, the tri-metallic FeCoNiP pre-catalysts exhibit exceptional apparent and intrinsic OER activities, outperforming many non-precious OER catalysts reported previously.

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wileyonlinelibrary.com Pt, Ir, and Ru, et al. are usually effective to boost the ORR or OER rate, [ 2,3 ] but their practical applications are severely limited by the prohibitive cost, scarce resource, and poor durability. Therefore, non-noble metal material and even non-metal material were explored for overcoming the limitation of the precious metal electrocatalysts for ORR and OER. [4][5][6] In particular, the bifunctional electrocatalysts for both OER and ORR reactions were highly desired for the unitized regenerative fuel cells (URECs), which can do the water electrolysis in regenerative mode and function in the other mode as a fuel cell recombining oxygen and hydrogen gas to produce electricity. Recently, Dai and co-workers [ 6 ] reported that the nitrogendoped carbon nanotubes (NCNTs) acted as an excellent electrocatalyst candidate with better electrocatalytic activity, long-term stability, and tolerance to crossover effect than the conventional Pt for ORR. Furthermore, the nitrogendoped carbon materials were found as the effi cient oxygen evolution electrocatalysts with comparable activity to those of iridium and cobalt oxide catalysts. [ 5 ] The N-doped carbon materials were with low cost, high catalytic activity, long durability, as well as abundant resource on earth, which were potential catalysts for oxygen electrochemistry and highly concerned recently. [ 5,7 ] The incorporation of nitrogen atoms into the carbon frameworks can effectively modulate the electronic structure of the surrounding carbon atoms and tune the local charge density distribution, [ 8 ] which results in the improvement of the chemical reactivity and subsequently promotes the catalytic performance. [ 9 ] In heterogeneous catalysis, the active sites of the catalysts are expected to be exposed at the surface which can be accessible to the reactants as much as possible in order to achieve high catalytic effi ciency. However, for most of routine NCNTs directly synthesized by chemical vapor deposition (CVD) growth and chemical doping, [ 6,10,11 ] the incorporated N atoms distributed uniformly in general, whereas the active sites induced by the dopant atoms in the inner walls of NCNTs were hardly accessible and consequently contributed to the catalytic property scarcely. Besides, the bamboo-like structure or the cup-stacked structure of the routine NCNTs render complex packing of graphene layers, which hinder the rapid electron The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play a decisive role for the effi ciency of fuel cells and metal-air batteries. The nitrogen doped carbon materials with low cost and long durability are potential catalysts to replace precious metal catalyst for oxygen electrochemistry; however, the unexposed active sites induced by the bulk dopant atoms are hardly accessible and consequently scarcely contribute to the catalytic property. In this study, carbon nanotubes (CNTs) are selected as the platform to demonstrate the potential of full exposure of 'active sites' at the surface. Nove...

Synergistic coupling of ruthenium with cobalt phosphide can significantly boost the hydrogen evolution performance of the hybrid catalysts in a wide pH range.

Ketonic carbonyl groups are catalytic active sites for oxidative dehydrogenation (ODH) reactions on carbon nanotubes. The quantity of these groups could be calculated from chemical titration with hydrazine compounds. ODH catalytic activity of nanocarbon is directly correlated with surface concentration of ketonic carbonyl groups, and the turnover frequency normalized by the number of active sites reflects the intrinsic activity of nanocarbon catalysts.

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The mechanism on interfacial synergistic catalysis for supported metal catalysts has long been explored and investigated in several important heterogeneous catalytic processes (e.g., water-gas shift (WGS) reaction). The modulation of metal-support interactions imposes a substantial influence on activity and selectivity of catalytic reaction, as a result of the geometric/electronic structure of interfacial sites. Although great efforts have validated the key role of interfacial sites in WGS over metal catalysts supported on reducible oxides, direct evidence at the atomic level is lacking and the mechanism of interfacial synergistic catalysis is still ambiguous. Herein, Ni nanoparticles supported on TiO (denoted as Ni@TiO) were fabricated via a structure topotactic transformation of NiTi-layered double hydroxide (NiTi-LDHs) precursor, which showed excellent catalytic performance for WGS reaction. In situ microscopy was carried out to reveal the partially encapsulated structure of Ni@TiO catalyst. A combination study including in situ and operando EXAFS, in situ DRIFTS spectra combined with TPSR measurements substantiates a new redox mechanism based on interfacial synergistic catalysis. Notably, interfacial Ni species (electron-enriched Ni site) participates in the dissociation of HO molecule to generate H, accompanied by the oxidation of Ni-O -Ti (O : oxygen vacancy) to Ni-O-Ti structure. Density functional theory calculations further verify that the interfacial sites of Ni@TiO catalyst serve as the optimal active site with the lowest activation energy barrier (∼0.35 eV) for water dissociation. This work provides a fundamental understanding on interfacial synergistic catalysis toward WGS reaction, which is constructive for the rational design and fabrication of high activity heterogeneous catalysts.