Modulating Water Splitting Kinetics via Charge Transfer and Interfacial Hydrogen Spillover Effect for Robust Hydrogen Evolution Catalysis in Alkaline Media.

Designing and synthesizing advanced electrocatalysts with superior intrinsic activity toward hydrogen evolution reaction (HER) in alkaline media is critical for the hydrogen economy. Herein, a novel Ir@Rhene heterojunction electrocatalyst is synthesized via epitaxially confining ultrasmall and low-coordinate Ir nanoclusters on the ultrathin Rh metallene accompanying the formation of Ir/IrO2 Janus nanoparticles. The as-prepared heterojunctions display outstanding alkaline HER activity, with an overpotential of only 17 mV at 10 mA cm-2 and an ultralow Tafel slope of 14.7 mV dec-1 . Both structural characterizations and theoretical calculations demonstrate that the Ir@Rhene heterointerfaces induce charge density redistribution, resulting in the increment of the electron density around the O atoms in the IrO2 site and thus delivering much lower water dissociation energy. In addition, the dual-site synergetic effects between IrO2 and Ir/Rh interface trigger and improve the interfacial hydrogen spillover, thereby subtly avoiding the steric blocking of the active site and eventually accelerating the alkaline HER kinetics.

Modified whey protein isolate gel prepared by thermal aggregation combined with transglutaminase crosslinking achieves Casein-like slow digestion in vitro and in vivo.

Our study aimed to fabricate a modified slow-digestive whey protein isolate (WPI), which can supply enough branched-chain amino acids (BCAAs) during long-term fasting. The WPI aqueous solution (10 % w/v) was treated by heat (80 ℃) to unfold the protein tertiary structure, and subsequently treated with transglutaminase to form a gel via cross-linking. The powder of the WPI gel was obtained by spray drying, which can dissolve in water easily and self-assemble into gels again. This modified WPI contained protein aggregates with high molecular weight, and kept a stable gel-like structure under simulated gastric digestion conditions (pH = 3, 37 ℃). A dense honeycomb internal microstructure of the freeze-dried gel was observed. Further, we found that the WPI gel successfully achieved a casein-like digestible ratio (37.37 %) and released more BCAAs (0.18 mg/mL) than casein during the 4 h of in vitro simulated digestion based on the INFOGEST method. Finally, our results showed that the C57BL/6 mice oral administrated with the modified WPI gel had consistently higher BCAAs concentration (0.052 mg/mL) in their blood serum than the mice with normal WPI intake during the 6 h of in vivo digestion.

Maximizing the peroxidase-like activity of Pd@PtxRu4-x nanocubes by precisely controlling the shell thickness and their application in colorimetric biosensors.

Although the application of nanoscale artificial enzymes in various industries is an attractive way to circumvent the intrinsic drawbacks of natural enzymes, their catalytic constant (Kcat) as a critical reaction parameter is far from satisfactory. Presented here is the rational design and fabrication of a unique peroxidase mimic catalyst based upon Pd@PtxRu4-x (1 ≤ x ≤ 3) prepared by coating PtRu alloy as conformal, ultrathin shells on Pd nanocrystals. Benefiting from an optimal Pt/Ru ratio and well-defined {100} facets, together with confining the Pt-Ru alloy to a shell of averagely 3.3-atomic-layer thick (i.e. Pd@Pt-Ru3.3L), the nanocrystals exhibit the highest catalytic activity and kinetics (1.2 × 106 s-1), resulting in a significant increase of catalytic activity compared with the classical PtRu nanozyme (3.6 × 103 s-1) and horseradish peroxidase (4.0 × 103 s-1), respectively. The following density functional theory calculations demonstrate that the origin of the superior catalytic performance could be attributed to the modulation of the adsorption behavior of the key reaction intermediates on the surface. As a proof of concept, its peroxidase mimicking ability is adopted for sensing glucose and glutathione molecules in human serum, with a long linear range and high selectivity. This work opens new horizons for the future development of advanced catalysts based upon alloy nanocrystals for various applications.