Single atoms are superior electrocatalysts having high atomic utilization and amazing activity for water oxidation and splitting. Herein, this work reports a thermal reduction method to introduce high‐valence iridium (Ir) single atoms into bimetal phosphide (FeNiP) nanoparticles toward high‐efficiency oxygen evolution reaction (OER) and overall water splitting. The presence of high‐valence single Ir atoms (Ir4+) and their synergistic interaction with Ni3+ species as well as the disproportionation of Ni3+ assisted by Fe collectively contribute to the exceptional OER performance. In specific, at appropriate Ir/Ni and Fe/Ni ratios, the as‐prepared Ir‐doped FeNiP (Ir25‐Fe16Ni100P64) nanoparticles at a mass loading of only 35 µg cm−2 show the overpotential as low as 232 mV at 10 mA cm−2 and activity as high as 1.86 A mg−1 at 1.5 V versus RHE for OER in 1.0 m KOH. Computational simulations confirm the vital role of high‐valence Ir to weaken the adsorption of OER intermediates, favorable for accelerating OER kinetics. Impressively, a Pt/C||Ir25‐Fe16Ni100P64 two‐electrode alkaline electrolyzer affords a current density of 10 mA cm−2 at a low cell voltage of 1.42 V, along with satisfied stability. An AA battery with a nominal voltage of 1.5 V can drive overall water splitting with obvious bubbles released.
By tuning the amount of the Se precursors during the synthesis, orthorhombic PdSe2, cubic Pd17Se15, and monoclinic Pd7Se2 nanoparticles are synthesized, respectively, which show phase-dependent electrocatalysis for ethanol oxidation reaction....
The cation-exchange strategy has shown great potential to create a large variety of inorganic nanostructures. We herein report the cation-exchange reactions between CdSe nanocrystals and Pd 2+ cations in different solvent environments and identify three features not sufficiently noticed before: (i) the exchange between Cd 2+ and Pd 2+ cations could be fully achieved in both aqueous and organic solvents and is also independent of its parent CdSe crystal structures; (ii) the exchange between Cd 2+ and Pd 2+ cations in aqueous solvent results in amorphous Pd−Se exchanged products, while in organic solvent, it leads to a cubic Pd 17 Se 15 phase; and (iii) the exchanged Pd 17 Se 15 product exhibits better electrocatalysis for ethanol oxidation reaction in an alkaline medium relative to its amorphous counterpart and the commercial Pd/C catalyst.
The catalytic activity and stability of palladium (Pd)-based electrocatalysts for ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR) can be improved by optimizing their composition and structure. Alloying tin (Sn) into Pd can induce electronic and synergistic effects, which weaken the adsorption of intermediate species (e.g., O and OH in ORR and CO in EOR) on Pd sites and even promote their further transformation. However, the SnPd alloys often suffer from complicated synthesis, large particle size, and inhomogeneity. In this context, we report the synthesis of SnPd nanoalloys with an ultrafine size of ca. 3.8 nm using a simple one-pot approach and their superior catalytic performance for EOR and ORR. Specifically, the SnPd alloy nanoparticles with an optimized Sn/Pd ratio of 18/82 show the mass and specific activity of 3.8 A mg −1 and 5.72 mA cm −2 , respectively, for EOR, while excellent performance for ORR with a half-wave potential of 0.92 V and specific activity of 3.46 mA cm −2 at 0.9 V, both of which are much higher than those of their commercial Pd/C and Pt/C counterparts.
Although remarkable advances are achieved in the development
of
novel and high-efficiency catalytic systems for H2 production
from the decomposition of dimethylamineborane in neat organic media,
there are few available reports on H2 production upon dimethylamineborane
hydrolysis. Hence, it is still of high importance to design and develop
efficient and highly selective catalysts for H2 production
upon dimethylamineborane hydrolysis. Herein, we have first designed
and synthesized a series of carbon nanosphere (CNS)-supported PtNi
bimetallic nanohybrids (PtNi/CNS), by immobilization of nearly monodispersed
PtNi bimetallic nanoparticles at the surface of CNSs, for the highly
selective and efficient H2 production from dimethylamineborane
hydrolysis. Among them, the optional Pt0.7Ni0.3/CNS nanohybrid exhibits the highest turnover frequency of 16,607
h–1, which exceeded most reported catalytic systems,
in the H2 generation from dimethylamineborane hydrolysis
at 30 °C under 0.3 M NaOH due to the superior synergistic effect.
The activation energy (E
a) of Pt0.7Ni0.3/CNS-catalyzed dimethylamineborane hydrolysis is
calculated to be 31.1 kJ/mol. Interestingly, the large kinetic isotope
effect of 2.76 with D2O verified that the breaking of a
water O–H bond is the rate-controlling step of dimethylamineborane
hydrolysis. This work presents a new, efficient, and durable Pt-based
nanocatalyst for H2 production from dimethylamineborane
hydrolysis.
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