This paper reports the performance of hydrogen evolution reaction (HER) electrocatalysts based on Pt thin film electrodes that are encapsulated by silicon oxide (SiO x ) nanomembranes. This membrane-coated electrocatalyst (MCEC) architecture offers a promising approach to enhancing electrocatalyst stability while incorporating advanced catalytic functionalities such as poison resistance and tunable reaction selectivity. Herein, a roomtemperature ultraviolet (UV) ozone synthesis process was used to systematically control the thickness of SiO x overlayers with nanoscale precision and evaluate their influence on the electrochemically active surface area (ECSA) and HER performance of the underlying Pt thin films. Through detailed characterization of the physical and electrochemical properties of the SiO x -encapsulated electrodes, it is shown that proton and H 2 transport occur primarily through the SiO x coating such that the HER takes place at the buried Pt|SiO x interface. Increasing the thickness of the SiO x overlayers results in monotonic increases in the overpotential losses of the MCEC electrodes. These overpotential losses were fit using a one-dimensional diffusion model, from which the H + and H 2 permeabilities through SiO x were obtained. Importantly, the SiO x nanomembranes were found to exhibit high selectivity for proton and H 2 transport in comparison to Cu 2+ , a model HER poison. Leveraging this property, we show that SiO x encapsulation can enable copperresistant operation of Pt HER electrocatalysts. It is expected that a more complete understanding of the structure−property− performance relationships of the SiO x overlayers will enable the design of stable MCECs capable of multifunctional catalysis with minimal loss in efficiency from concentration overpotential losses associated with mass transport through SiO x .

Purpose Binder jetting (BJ) process is an additive manufacturing (AM) process in which powder materials are selectively joined by binder materials. Products can be manufactured layer-by-layer directly from three-dimensional model data. The quality properties of the products fabricated by the BJ AM process are significantly affected by the process parameters. To improve the product quality, the optimal process parameters need to be identified and controlled. This research works with the 420 stainless steel powder material. Design/methodology/approach This study focuses on four key printing parameters and two end-product quality properties. Sixteen groups of orthogonal experiment designed by the Taguchi method are conducted, and then the results are converted to signal-to-noise ratios and analyzed by analysis of variance. Findings Five sets of optimal parameters are concluded and verified by four group confirmation tests. Finally, by taking the optimal parameters, the end-product quality properties are significantly improved. Originality/value These optimal parameters can be used as a guideline for selecting proper printing parameters in BJ to achieve the desired properties and help to improve the entire BJ process ability.

Precise control of electron density at catalyst active sites enables regulation of surface chemistry for the optimal rate and selectivity to products. Here, an ultrathin catalytic film of amorphous alumina (4 nm) was integrated into a catalytic condenser device that enabled tunable electron depletion from the alumina active layer and correspondingly stronger Lewis acidity. The catalytic condenser had the following structure: amorphous alumina/graphene/HfO 2 dielectric (70 nm)/p-type Si. Application of positive voltages up to +3 V between graphene and the p-type Si resulted in electrons flowing out of the alumina; positive charge accumulated in the catalyst. Temperatureprogrammed surface reaction of thermocatalytic isopropanol (IPA) dehydration to propene on the charged alumina surface revealed a shift in the propene formation peak temperature of up to ΔT peak ∼50 °C relative to the uncharged film, consistent with a 16 kJ mol −1 (0.17 eV) reduction in the apparent activation energy. Electrical characterization of the thin amorphous alumina film by ultraviolet photoelectron spectroscopy and scanning tunneling microscopy indicates that the film is a defective semiconductor with an appreciable density of in-gap electronic states. Density functional theory calculations of IPA binding on the pentacoordinate aluminum active sites indicate significant binding energy changes (ΔBE) up to 60 kJ mol −1 (0.62 eV) for 0.125 e − depletion per active site, supporting the experimental findings. Overall, the results indicate that continuous and fast electronic control of thermocatalysis can be achieved with the catalytic condenser device.

This article identifies Pt-oxide interlayers at the buried interface of Si-oxide/Pt thin films and explores their implications for electrocatalysis.