Protonic ceramic fuel cells, like their higher-temperature solid-oxide fuel cell counterparts, can directly use both hydrogen and hydrocarbon fuels to produce electricity at potentially more than 50 per cent efficiency. Most previous direct-hydrocarbon fuel cell research has focused on solid-oxide fuel cells based on oxygen-ion-conducting electrolytes, but carbon deposition (coking) and sulfur poisoning typically occur when such fuel cells are directly operated on hydrocarbon- and/or sulfur-containing fuels, resulting in severe performance degradation over time. Despite studies suggesting good performance and anti-coking resistance in hydrocarbon-fuelled protonic ceramic fuel cells, there have been no systematic studies of long-term durability. Here we present results from long-term testing of protonic ceramic fuel cells using a total of 11 different fuels (hydrogen, methane, domestic natural gas (with and without hydrogen sulfide), propane, n-butane, i-butane, iso-octane, methanol, ethanol and ammonia) at temperatures between 500 and 600 degrees Celsius. Several cells have been tested for over 6,000 hours, and we demonstrate excellent performance and exceptional durability (less than 1.5 per cent degradation per 1,000 hours in most cases) across all fuels without any modifications in the cell composition or architecture. Large fluctuations in temperature are tolerated, and coking is not observed even after thousands of hours of continuous operation. Finally, sulfur, a notorious poison for both low-temperature and high-temperature fuel cells, does not seem to affect the performance of protonic ceramic fuel cells when supplied at levels consistent with commercial fuels. The fuel flexibility and long-term durability demonstrated by the protonic ceramic fuel cell devices highlight the promise of this technology and its potential for commercial application.

BaCo0.4Fe0.4Zr0.1Y0.1O3−δis applied for the first time as a cathode for low-temperature solid oxide fuel cells (LT-SOFCs) with high power densities below 500 °C and 2500 hours stable performance.

Terpenoids are natural compounds predominantly present in plants. They have many pharmaceutical and/or nutritional functions, and have been widely applied in medical, food, and cosmetics industries. Recently, terpenoids have been used in the clinical treatment of COVID-19 due to the good antiviral activities. The increasing demand for terpenoids in international markets poses a serious threat to many plant species. For environmentally sustainable development, microbial cell factories have been utilized as the promising platform to produce terpenoids. Nevertheless, the bioproduction of most terpenoids cannot meet commercial requirements due to the low cost-benefit ratio until now. The biosynthetic potential of endophytes has gained attention in recent decades owing to the continual discovery of endophytes capable of synthesizing plant bioactive compounds. Accordingly, endophytes could be alternative sources of terpenoid-producing strains or terpenoid synthetic genes. In this review, we summarized the research progress describing the main and supporting roles of endophytes in terpenoid biosynthesis and biotransformation, and discussed the current problems and challenges which may prevent the further exploitation. This review will improve our understanding of endophyte resources for terpenoid production in industry in the future. Key points • The mechanisms employed by endophytes in terpenoid synthesis in vivo and in vitro.• Endophytes have the commercial potentials in terpenoid bioproduction and biotransformation.• Synthetic biology and multiomics will improve terpenoid bioproduction in engineered cell factories.