Electronic Modulation and Mechanistic Study of Ru-Decorated Porous Cu-Rich Cuprous Oxide for Robust Alkaline Hydrogen Oxidation and Evolution Reactions.

Rational design of high-efficiency and viable electrocatalysts is essential in overcoming the bottleneck of sluggish alkaline hydrogen oxidation/evolution reaction (HOR/HER) kinetics. In this study, a metal-organic framework-derived strategy for constructing a Pt-free catalyst with Ru clusters anchored on porous Cu-Cu2 O@C is proposed. The designed Ru/Cu-Cu2 O@C exhibits superior HOR performance, with a mass activity of 2.7 mA µ g R u - 1 ${{{\rm \mu }{\rm g}}_{{\rm R}{\rm u}}^{-1}}$ at 50 mV, which is about 24 times higher than that of state-of-the-art Pt/C (0.11 mA µ g P t - 1 ${{{\rm \mu }{\rm g}}_{{\rm P}{\rm t}}^{-1}}$ ). Significantly, Ru/Cu-Cu2 O@C also displays impressive HER performance by generating 26 mV at 10 mA cm-2 , which exceeds the majority of documented Ru-based electrocatalysts. Systematic characterization and density functional theory (DFT) calculations reveal that efficient electron transfer between Ru and Cu species results in an attenuated hydrogen binding energy (HBE) of Ru and an enhanced hydroxy binding energy (OHBE) of Cu2 O, together with an optimized H2 O adsorption energy with Cu2 O as the H2 O*-capturing site, which jointly facilitates HOR and HER kinetics.

The effects of Al-doped to cathode material based on hollow microspheres of nickel-manganese on sodium-ion batteries.

Sodium-ion batteries (SIBs) are expected to be a great substitute for lithium ion batteries. Although there are many difficulties to overcome, SIBs have become one of the most important research areas for large-scale energy storage equipment. The spherical particles are conducive to the contact between the cathode material and the electrolyte, which could increase the electrochemical reaction area, and improve the deintercalation rate of sodium ions during charging and discharging. In this paper, a precipitation method was used to prepare spherical MnCO3material as template and raw material. After all the raw materials were weighed with the molar ratios of Na0.67Mn0.67-0.75xNi0.33AlxO2, a series of hollow micro-spherical sodium-ion cathode materials were synthesized by the conventional high-temperature solid-state method. The effects of Al-doped on the structure and electrochemical performance of Na0.67Ni0.33Mn0.67O2was studied, and it was founded that the samples doped with Al had smaller particle size than that without Al. The electrochemical tests showed that Na0.67Mn0.595Ni0.33Al0.1O2(x= 0.1) exhibite superior high-rate capabilities and cyclic stability. And the hollow microsphere structure has a higher capacity, the first discharge capacity at 0.1C reach 128 mAh g-1.

Structure-regulated Ru particles decorated P-vacancy-rich CoP as a highly active and durable catalyst for NaBH4 hydrolysis.

NaBH4 is considered the best hydrogen storage material due to its high hydrogen content of 10.6 wt% and good stability. However, NaBH4 hydrolysis requires an efficient catalyst because of the sluggish reaction kinetics. In this work, we have demonstrated a process of preparing a cobalt phosphide-supported Ru particulate nanocatalyst with abundant phosphorus vacancies for the first time. Electron paramagnetic resonance and transmission electron microscopy revealed that the synthesized Ru9.8/r-CoP catalyst has ample phosphorus vacancies, and Ru species are small particles (~2.5 nm) with uniform dispersion, respectively. More importantly, the optimized Ru9.8/r-CoP catalyst has the lowest activation energy (45.3 kJ mol-1) and exhibits excellent catalytic performance for NaBH4 hydrolysis with a high hydrogen generation rate 9783.3 mLH2 min-1 gcat-1 at 25 °C, which is higher than most of the cobalt-based catalysts. Moreover, the Ru9.8/r-CoP catalyst also shows good reusability. For example, the catalytic performance only declined by ca. 14% after five cycles. The excellent catalytic performance of Ru9.8/r-CoP is attributed to the abundant phosphorus vacancies along with a large specific surface area of r-CoP, which makes the Ru particles smaller and more uniformly dispersed on the surface, thereby exposing more active sites to show improved performance.