Sixteen coals from brown to bituminous coal have been pyrolyzed in high-purity He at 400 K/min up to 1000 °C with a fixed bed reactor, and the nitrogen distribution has been examined in detail. Nitrogen mass balances fall within 96−103%. Not only volatile nitrogen (HCN, NH3, and tar) but also N2 is formed, and among these N2 is the dominant product for almost all of the coals. Conversion of coal nitrogen to N2 depends strongly on coal type. A German brown coal gives the highest conversion of ≈60%, followed by ≈50% from a Chinese lignite. No relationship between N2 formation and coal rank is observed. As N2 increases, volatile nitrogen decreases slightly, but char nitrogen decreases remarkably, which means a strong, reverse correlation between N2 and char nitrogen. When the lignite char devolatilized at 600 °C is heated to 1000 °C, conversion of the nitrogen to N2 proceeds almost exclusively. These observations show that N2 originates mostly from char nitrogen and/or precursors. The mechanism of N2 formation is discussed mainly in terms of the catalysis of solid phase reactions by Fe-containing minerals in low-rank coals.

Lead‐free Cs2AgBiBr6 double perovskite has received widespread attention because of its non‐toxicity and high thermal stability. However, intrinsic bromide ion (Br–) migration limits continuous operation of Cs2AgBiBr6‐based perovskite solar cells (PSCs). Herein, an operational and simple strategy is carried out to improve the power conversion efficiency (PCE) and long‐term stability of Cs2AgBiBr6‐based PSCs by introducing 1‐butyl‐1‐methylpyrrolidinium chloride (BMPyrCl) and 1‐butyl‐3‐methylpyridinium chloride (BMPyCl) ionic liquids (ILs). The higher binding energy between Br– in Cs2AgBiBr6 and cation in IL containing pyrrole can inhibit Br– migration effectively, thereby reducing film defects and improving energy level matching. The optimized PCE of 2.22% is obtained for hole transport layer‐free, carbon‐based PSC, which hardly degrades at 40% ± 5% relative humidity and 25 °C for 40 days. This work highlights an effective method to mitigate the halide migration in Cs2AgBiBr6 perovskite, thus providing an effective route in promoting the development of lead‐free double PSCs.

Low-rank coals have been pyrolyzed in high-purity He under different conditions with a fixed bed reactor, and factors controlling N 2 formation have been examined. N 2 is the dominant product at g800 °C after almost complete release of tar-N, HCN, and NH 3 . Heating rate (10-1400 °C/ min) affects N 2 slightly. In contrast, conversion of coal-N to N 2 increases remarkably with increasing temperature with a corresponding decrease in char-N and reaches 65-70% at 1200 °C. These data lead to a strong, reverse correlation between N 2 and char-N, which shows that char-N and/or precursors are the major source of N 2 . Demineralization removes mainly Fe-and Ca-containing minerals and results in a drastic decrease in conversion to N 2 . Addition of a nanophase iron catalyst after demineralization promotes N 2 formation, whereas Ca(OH) 2 has no significant effect on it. Upon pyrolysis, Fe-containing minerals probably in the ion-exchangeable forms are transformed into fine particles of metallic iron, which are responsible for the remarkable formation of N 2 from low-rank coals. Catalysis by the mineral-derived iron is discussed in terms of interactions with char-N in the solid phase.

The unprecedented advancement in power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) has rendered them a promising game‐changer in photovoltaics. However, unsatisfactory environmental stability and high manufacturing cost of window electrodes are bottlenecks impeding their commercialization. Here, a strategy is introduced to address these bottlenecks by replacing the costly indium tin oxide (ITO) window electrodes via a simple transfer technique with single‐walled carbon nanotubes (SWCNTs) films, which are made of earth‐abundant elements with superior chemical and environmental stability. The resultant devices exhibit PCEs of ≈19% on rigid substrates, which is the highest value reported to date for ITO‐free PSCs. The facile approach for SWCNTs also enables application in flexible PSCs (f‐PSCs), delivering a PCE of ≈18% with superior mechanical robustness over their ITO‐based counterparts due to the excellent mechanical properties of SWCNTs. The SWCNT‐based PSCs also deliver satisfactory performances on large‐area (1 cm2 active area in this work). Furthermore, these SWCNT‐based PSCs can retain over 80% of original PCEs after exposure to air over 700 h while ITO‐based devices only sustain ≈60% of initial PCEs. This work paves a promising way to accelerate the commercialization of ITO‐free PSCs with reduced material cost and prolonged lifetimes.

The oil yield and quality of pyrolysis oil from microwave heating of biomass was established by studying the behaviour of Larch in microwave processing. This is the first study in biomass pyrolysis to use a microwave processing technique and methodology that is fundamentally scalable, from which the basis of design for a continuous processing system can be derived to maximise oil yield and quality. It is shown systematically that sample size is a vital parameter that has been overlooked by previous work in this field. When sample size is controlled the liquid product yield is comparable to conventional pyrolysis, and can be achieved at an energy input of around 600 kWh/t. The quality of the liquid product is significantly improved compared to conventional pyrolysis processes, which results from the very rapid heating and quenching that can be achieved with microwave processing. The yields of Levoglucosan and phenolic compounds were found to be an order of magnitude higher in microwave pyrolysis when compared with conventional fast pyrolysis. Geometry is a key consideration for the development of a process at scale, and the opportunities and challenges for scale-up are discussed within this paper.