Solar water splitting provides a promising path for sustainable hydrogen production and solar energy storage. One of the greatest challenges towards large-scale utilization of this technology is reducing the hydrogen production cost. The conventional electrolyser architecture, where hydrogen and oxygen are co-produced in the same cell, gives rise to critical challenges in photoelectrochemical water splitting cells that directly convert solar energy and water to hydrogen. Here we overcome these challenges by separating the hydrogen and oxygen cells. The ion exchange in our cells is mediated by auxiliary electrodes, and the cells are connected to each other only by metal wires, enabling centralized hydrogen production. We demonstrate hydrogen generation in separate cells with solar-to-hydrogen conversion efficiency of 7.5%, which can readily surpass 10% using standard commercial components. A basic cost comparison shows that our approach is competitive with conventional photoelectrochemical systems, enabling safe and potentially affordable solar hydrogen production.

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Alternative fuels are essential to enable the transition to a sustainable and environmentally friendly energy supply. Synthetic fuels derived from renewable energies can act as energy storage media, thus mitigating the effects of fossil fuels on environment and health. Their economic viability, environmental impact, and compatibility with current infrastructure and technologies are fuel and power source specific. Nitrogen-based fuels pose one possible synthetic fuel pathway. In this review, we discuss the progress and current research on utilization of nitrogen-based fuels in power applications, covering the complete fuel cycle. We cover the production, distribution, and storage of nitrogen-based fuels. We assess much of the existing literature on the reactions involved in the ammonia to nitrogen atom pathway in nitrogen-based fuel combustion. Furthermore, we discuss nitrogen-based fuel applications ranging from combustion engines to gas turbines, as well as their exploitation by suggested end-uses. Thereby, we evaluate the potential opportunities and challenges of expanding the role of nitrogen-based molecules in the energy sector, outlining their use as energy carriers in relevant fields.

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Photoelectrochemical (PEC) water splitting offers an elegant approach for solar energy conversion into hydrogen fuel. Large-scale hydrogen production requires stable and efficient photoelectrodes and scalable PEC cells that are fitted for safe and cost-effective operation. One of the greatest challenges is the collection of hydrogen gas from millions of PEC cells distributed in the solar field. In this work, a separate-cell PEC system with decoupled hydrogen and oxygen cells was designed for centralized hydrogen production, using 100 cm 2 hematite (-Fe 2 O 3) photoanodes and nickel hydroxide (Ni(OH) 2) / oxyhydroxide (NiOOH) electrodes as redox mediators. The operating conditions of the system components and their configuration were optimized for daily cycles, and ten 8.3 h cycles were carried out under solar simulated illumination without additional bias at an average short-circuit current of 55.2 mA. These results demonstrate successful operation of a decoupled PEC water splitting system with separate hydrogen and oxygen cells.

We report here a new approach for the modification of the performance of metal catalysts: organic doping of the metal. Specifically, we report that the doping of Ag with Congo Red (CR@Ag) significantly improves the performance of Ag as a catalyst for methanol oxidation to formaldehyde, outperforming both pure Ag and CR‐coated Ag (CR/Ag) in terms of lowering the temperature needed for maximal conversion by 100 °C, lowering the temperature by 200 °C to reach the maximal selectivity (aldehyde formation), and increasing the maximal space velocity by a factor of two. We were led to this discovery by a detailed investigation of the thermal behavior (thermogravimetric and differential thermal analysis and mass spectroscopy) of CR@Ag under an oxidative atmosphere, which has indicated that the metal is strongly catalyzing the CR oxidation, and which pointed to the relevant temperature for activation of the catalyst.

We describe a new type of composite material:  polymers entrapped within a metal. Polystyrene-sulfonic acid and poly(vinyl alcohol) were entrapped within silver. Detailed procedures for the entrapment are provided, and it is shown that this entrapment is a distinctly different process from polymer adsorption on the metal surface. Characterization of these new composites includes XRD measurements, SEM with EDAX, surface area, porosity, and density measurements, and full oxidative degradation analysis by thermogravimetry (TGA/DTA/DTG) coupled to mass spectrometry. A pronounced effect of the metal caging on the thermal degradation of the two entrapped polymers was observed. On the basis of all experimental observations a proposition is made as to the molecular level picture of the entrapment.