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Abstract Concerning both the activity and stability of the promising solar-driven Ta3N5-based photoanodes for photoelectrochemical water splitting, the strategy for simultaneously promoting charge separation, enhancing catalytic activity and also improving the resistance to self-oxidation is highly desirable and actively pursued. In this study, a novel dual co-catalyst shell consisting of a continuous CoPi layer at the bottom and many non-continuous Co(OH)2 islands at the top of the CoPi layer is designed to meet the strict requirements for efficient Ta3N5 photoanodes. As a result of the synergistic effects of such a shell in collectively addressing the concerns, the constructed photoanode of CoPi/Co(OH)2-Ta3N5 nanorod arrays show the remarkably enhanced photoelectrochemical water splitting performance compared with the photoanodes with single co-catalyst. The results demonstrated in this study are expected to shed some light on constructing efficient photoelectrodes of the light absorbers that have wide absorption range but low resistance to self-oxidation.

AbstractImproving the long-term stability of perovskite solar cells is critical to the deployment of this technology. Despite the great emphasis laid on stability-related investigations, publications lack consistency in experimental procedures and parameters reported. It is therefore challenging to reproduce and compare results and thereby develop a deep understanding of degradation mechanisms. Here, we report a consensus between researchers in the field on procedures for testing perovskite solar cell stability, which are based on the International Summit on Organic Photovoltaic Stability (ISOS) protocols. We propose additional procedures to account for properties specific to PSCs such as ion redistribution under electric fields, reversible degradation and to distinguish ambient-induced degradation from other stress factors. These protocols are not intended as a replacement of the existing qualification standards, but rather they aim to unify the stability assessment and to understand failure modes. Finally, we identify key procedural information which we suggest reporting in publications to improve reproducibility and enable large data set analysis.

Abstract In order to assess the feasibility of utilizing renewable hydrogen as transport fuel for fuel cell vehicles, four possible low-carbon hydrogen supply routes for a hydrogen refueling station located in Shanghai are studied. Route Ⅰ and II are onsite hydrogen supply routes powered by a stand-alone or grid-connected photovoltaic (PV)-wind generation system separately. Route Ⅲ and IV are offsite hydrogen supply routes, in which hydrogen is produced by a stand-alone or grid-connected PV-wind generation system located in Qinghai Province respectively and delivered via liquid hydrogen truck to Shanghai. The microgrid system for hydrogen production is designed and optimized with the aid of HOMER Pro® software. The results show that in hydrogen production stage, Route Ⅳ shows the best economic performance, both in the total net present cost (NPC) cost and levelized cost of energy (LCOE) cost. As for the whole hydrogen supply chain, Route IV is also the most economic hydrogen supply way, the levelized cost of hydrogen (LCOH) of which is slightly lower than that of Route II. The sensitivity results show that the total LCOH cost of Route Ⅳ is feasible based on the current shorter electrolyzer's lifetime. Therefore, it indicates that nowadays, producing hydrogen from a grid connected PV-wind hybrid power system in renewable energy rich area (Qinghai Province) and delivering it via liquid hydrogen truck to a refueling station in east coast area (Shanghai) of China may be a feasible solution.

We reported the realization of assembling compact-designed supercapacitors using large-scaled free-standing and flexible single-walled carbon nanotube (SWCNT) films as both anode and cathode. A prototype of the processing procedures was developed to obtain the uniform spreading of the SWCNT films onto the separators serving as both electrodes and charge collectors without metallic current collectors, leading to a simplified and lightweight architecture. The area of SWCNT film on a separator can be scaled up and its thickness can be extended. High energy and power densities (43.7 Wh kg−1 and 197.3 kW kg−1, respectively) were achieved from the prepared SWCNT film-based compact-designed supercapacitors with small equivalent series resistance. The specific capacitance of this kind of compact-designed SWCNT film supercapacitor is about 35 F g−1. These results clearly show the potential application of free-standing SWCNT film in compact-designed supercapacitor with enhanced performance and significantly improved energy and power densities.

Hierarchical TiC hollow branched fibres are synthesized and demonstrate high-rate supercapacitor energy storage with remarkable wide-temperature specific capacitance and excellent cycling stability.

Abstract China has dominated the global aluminum production and consumption in the past few decades, therefore it is of particular interest to stakeholders in China and worldwide to explore whether such aluminum boom will continue or not in China. This study applies a scenario-based dynamic material flow analysis to quantify the stocks and flows along the anthropogenic aluminum cycle in China from 1950 to 2100. Potential future changes of significant parameters are explored and identified, and around 250 sets of scenario results (including all flows, stocks, and losses along the aluminum cycle in China) are obtained for the comprehensive scenario analysis. The main findings include: (1) China's primary aluminum production will peak at around 40 MMT (million metric tons) at around 2025, leading to the end of primary aluminum boom that started from the early 1990s; (2) Domestic aluminum demand will continue to increase to more than 40 MMT due to the growing accumulation of in-use stocks in meeting future societal needs; (3) China's old aluminum scrap generation will increase dramatically (around 0.8 MMT per year) soon and secondary production will account for more than 60% of aluminum production after 2050s in almost all scenarios. Thus, there will be a rapid shifting in production capacity from primary to secondary routes. In this context, the corresponding policy should focus more on the urban mining, and improvement of end-of-life management systems and sorting technologies. These scenario results also reveal key opportunities and barriers in the process. Notably, it becomes increasingly important for China's and the global aluminum industry to investigate China's future role in the global market of primary and waste aluminum products.