| 1 | Oxidative coupling of methane over LaAlO3 perovskite catalysts prepared by a co-precipitation method: Effect of co-precipitation pH value显示文摘Oxidative coupling of methane(OCM) was conducted over LaAlO3X catalysts that were prepared by a coprecipitation method using different co-precipitation pH values(X = 6–10). The aim is to investigate the effect of p H values on the catalytic activity of La AlO3 catalysts in this reaction. The results showed that the co-precipitation pH value affected greatly on the formation of chemical species of precipitate precursors in the co-precipitation step, leading to different phases of the finally obtained LaAlO3 catalysts.When the co-precipitation pH value increased up to 8, the lanthanum-related phases such as La2 O3 and La(OH)3 were gradually formed as by-products, preventing the formation of LaAlO3 perovskite crystalline structure and facilitating the formation of oxygen vacancies on catalyst surface. However, at pH value of9 or higher, the lanthanum content in the precipitate precursor was increased greatly. Not LaAlO3 perovskite but lanthanum-related phases were developed as main phases, reducing their catalytic activities in this reaction. Among LaAlO3 catalysts, the one prepared at pH = 8 showed the highest C2 yield due to its well-developed oxygen vacancies and electrophilic lattice oxygen. Therefore, the co-precipitation pH value strongly affected the LaAlO3 catalyst activity in OCM reaction. A precious pH control should be required to prepare various perovskite catalysts for the OCM. | Yujin Sim Jihoon Yoo Jeong-Myeong Ha Ji Chul Jung | 2019 | Journal of Energy Chemistry2019，28，8： | 4 |
| 2 | A sulfur self-doped multifunctional biochar catalyst for overall water splitting and a supercapacitor from Camellia japonica flowers显示文摘A versatile use of a sulfur self-doped biochar derived from Camellia japonica(camellia)flowers is demonstrated as a multifunctional catalyst for overall water splitting and a supercapacitor.The native sulfur content in the camellia flower facilitates in situ self-doping of sulfur,which highly activates the camellia-driven biochar(SA-Came)as a multifunctional catalyst with the enhanced electron-transfer ability and long-term durability.For water splitting,an SA-Came-based electrode is highly stable and shows reaction activities in both hydrogen and oxygen evolution reactions,with overpotentials of 154 and 362 mV at 10 mA cm^(−2),respectively.For supercapacitors,SA-Came achieves a specific capacitance of 125.42 F g^(−1)at 2 A g^(−1)and high cyclic stability in a three-electrode system in a 1 M KOH electrolyte.It demonstrated a high energy density of 34.54 Wh kg^(−1)at a power density of 1600 W kg^(−1)as a symmetric hybrid supercapacitor device with a wide working potential range of 0-1.6 V. | Chengkai Xia Subramani Surendran Seulgi Ji Dohun Kim Yujin Chae Jaekyum Kim Minyeong Je Mi-Kyung Han Woo-Seok Choe Chang Hyuck Choi Heechae Choi Jung Kyu Kim Uk Sim | 2022 | Carbon Energy2022，4，4： | 3 |
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