High-entropy alloys (HEAs) with unique physicochemical properties have attracted tremendous attention in many fields, yet the precise control on dimension and morphology at atomic level remains ...formidable challenges. Herein, we synthesize unique PtRuNiCoFeMo HEA subnanometer nanowires (SNWs) for alkaline hydrogen oxidation reaction (HOR). The mass and specific activities of HEA SNWs/C reach 6.75 A mg
and 8.96 mA cm
, respectively, which are 2.8/2.6, 4.1/2.4, and 19.8/18.7 times higher than those of HEA NPs/C, commercial PtRu/C and Pt/C, respectively. It can even display enhanced resistance to CO poisoning during HOR in the presence of 1000 ppm CO. Density functional theory calculations reveal that the strong interactions between different metal sites in HEA SNWs can greatly regulate the binding strength of proton and hydroxyl, and therefore enhances the HOR activity. This work not only provides a viable synthetic route for the fabrication of Pt-based HEA subnano/nano materials, but also promotes the fundamental researches on catalysis and beyond.
Designing electrocatalysts with high-performance for both reduction and oxidation reactions faces severe challenges. Here, the uniform and ultrasmall (~3.4 nm) high-entropy alloys (HEAs) Pt
Ni
Fe
Co
...Cu
nanoparticles are synthesized by a simple low-temperature oil phase strategy at atmospheric pressure. The Pt
Ni
Fe
Co
Cu
/C catalyst exhibits excellent electrocatalytic performance for hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR). The catalyst shows ultrasmall overpotential of 11 mV at the current density of 10 mA cm
, excellent activity (10.96 A mg
at -0.07 V vs. reversible hydrogen electrode) and stability in the alkaline medium. Furthermore, it is also the efficient catalyst (15.04 A mg
) ever reported for MOR in alkaline solution. Periodic DFT calculations confirm the multi-active sites for both HER and MOR on the HEA surface as the key factor for both proton and intermediate transformation. Meanwhile, the construction of HEA surfaces supplies the fast site-to-site electron transfer for both reduction and oxidation processes.
The charge transfer phenomenon of contact electrification even exists in the liquid-solid interface by a tiny droplet on the solid surface. In this work, we have investigated the contact ...electrification mechanism at the liquid-solid interface from the electronic structures at the atomic level. The electronic structures display stronger modulations by the outmost shell charge transfer via surface electrostatic charge perturbation than the inter-bonding-orbital charge transfer at the liquid-solid interface, supporting more factors being involved in charge transfer via contact electrification. Meanwhile, we introduce the electrochemical cell model to quantify the charge transfer based on the pinning factor to linearly correlate the charge transfer and the electronic structures. The pinning factor exhibits a more direct visualization of the charge transfer at the liquid-solid interface. This work supplies critical guidance for describing, quantifying, and modulating the contact electrification induced charge transfer systems in triboelectric nanogenerators in future works.
Channel‐rich RuCu snowflake‐like nanosheets (NSs) composed of crystallized Ru and amorphous Cu were used as efficient electrocatalysts for oxygen evolution reaction (OER), hydrogen evolution reaction ...(HER), and overall water splitting in pH‐universal electrolytes. The optimized RuCu NSs/C‐350 °C and RuCu NSs/C‐250 °C show attractive activities of OER and HER with low overpotentials and small Tafel slopes, respectively. When applied to overall water splitting, the optimized RuCu NSs/C can reach 10 mA cm−2 at cell voltages of only 1.49, 1.55, 1.49 and 1.50 V in 1 m KOH, 0.1 m KOH, 0.5 m H2SO4 and 0.05 m H2SO4, respectively, much lower than those of commercial Ir/C∥Pt/C. The optimized electrolyzer exhibits superior durability with small potential change after up to 45 h in 1 m KOH, showing a class of efficient functional electrocatalysts for overall water splitting.
Channel rich RuCu nanosheets (NSs) have been successfully prepared and applied as a highly active and stable bifunctional electrocatalyst for the oxygen evolution reaction, hydrogen evolution reaction, as well as overall water splitting. This system is one of the best electrocatalysts reported to date.
Direct methane conversion (DMC) to high value-added products is of significant importance for the effective utilization of CH
to combat the energy crisis. However, there are ongoing challenges in DMC ...associated with the selective C-H activation of CH
. The quest for high-efficiency catalysts for this process is limited by the current drawbacks including poor activity and low selectivity. Here we show a cerium dioxide (CeO
) nanowires supported rhodium (Rh) single-atom (SAs Rh-CeO
NWs) that can serve as a high-efficiency catalyst for DMC to oxygenates (i.e., CH
OH and CH
OOH) under mild conditions. Compared to Rh/CeO
nanowires (Rh clusters) prepared by a conventional wet-impregnation method, CeO
nanowires supported Rh single-atom exhibits 6.5 times higher of the oxygenates yield (1231.7 vs. 189.4 mmol g
h
), which largely outperforms that of the reported catalysts in the same class. This work demonstrates a highly efficient DMC process and promotes the research on Rh single-atom catalysts in heterogeneous catalysis.
Pursuing active and durable water splitting electrocatalysts is of vital significance for solving the sluggish kinetics of the oxygen evolution reaction (OER) process in energy supply. Herein, ...theoretical calculations identify that the local distortion-strain effect in amorphous RuTe
system abnormally sensitizes the Te-pπ coupling capability and enhances the electron-transfer of Ru-sites, in which the excellent inter-orbital p-d transfers determine strong electronic activities for boosting OER performance. Thus, a robust electrocatalyst based on amorphous RuTe
porous nanorods (PNRs) is successfully fabricated. In the acidic water splitting, a-RuTe
PNRs exhibit a superior performance, which only require a cell voltage of 1.52 V to reach a current density of 10 mA cm
. Detailed investigations show that the high density of defects combine with oxygen atoms to form RuO
H
species, which are conducive to the OER. This work offers valuable insights for constructing robust electrocatalysts based on theoretical calculations guided by rational design and amorphous materials.
PDF
