Summary Quantitative comparison of photocatalytic performances across different photocatalysis setups is technically challenging. Here, we combine the concepts of relative and optimal photonic efficiencies to normalize activities with an internal benchmark material, RuO 2 photodeposited on a P25-TiO 2 photocatalyst, which was optimized for reproducibility of the oxygen evolution reaction (OER). Additionally, a general set of good practices was identified to ensure reliable quantification of photocatalytic OER, including photoreactor design, photocatalyst dispersion, and control of parasitic reactions caused by the sacrificial electron acceptor. Moreover, a method combining optical modeling and measurements was proposed to quantify the benchmark absorbed and scattered light (7.6% and 81.2%, respectively, of λ = 300–500 nm incident photons), rather than just incident light (≈AM 1.5G), to estimate its internal quantum efficiency (16%). We advocate the adoption of the instrumental and theoretical framework provided here to facilitate material standardization and comparison in the field of artificial photosynthesis.

The rational design of highly active electrocatalysts for the ethanol electrooxidation reaction (EOR) is important for future commercial applications of efficient direct ethanol fuel cells. Herein, we describe application of a solid-phase reaction for the creation of a well-defined, high-efficiency, nanoporous gold (NPG) electrocatalyst for EOR. The evaluation of the feature size and physical properties of the NPG electrocatalysts was undertaken using field-emission scanning electron microscopy and high-resolution transmission electron microscopy. Additionally, the catalytic performance of the prepared NPG electrocatalysts was determined using cyclic voltammetry (CV) and chronoamperometry (CA), with results indicating that their enhanced electrocatalytic activities and long-term durability were highly dependent upon morphology. The created NPG exhibited a mass activity of 308 mA mgAu –1 toward EOR in alkaline media, which is much higher than those of nanostructured Au catalysts. In particular, 800-cycle CV and 2000-s CA tests in alkaline solution consistently suggested excellent long-term stability and durability of the NPG. Our findings suggest the developed NPG as a promising electrocatalyst and an ideal substrate for multifunctional electrocatalysts for EOR.

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Nanoporous metals (NPMs) possess a number of intriguing properties that result in NPMs being an important family of nanomaterials for many advanced applications. However, the methods of preparing NPMs are relatively complicated and have many limitations, which have hindered the commercial application of NPMs thus far. By introducing metal-induced crystallization, a solid-phase reaction method for preparing NPMs was developed in this study, which is highly efficient and environmentally friendly. The microstructure of the prepared nanoporous gold (NPG) was characterized on an atomic scale by scanning electron microscopy and high-resolution transmission electron microscopy. The results confirmed that the solid-phase reaction method is an effective alternative means of preparing highly pure NPG. The results of electrochemical tests demonstrated that thus-prepared NPG possesses higher electrocatalytic activity than other types of gold electrodes toward oxygen reduction in alkaline media. The combination of a simple preparation process and higher activity suggests that the developed method may promote the future use of NPG in new energy applications, such as fuel cells and metal-air batteries.