Yi Wei,Jiale Xie,Chaoyue Shen,Licong Lu,Jianbing Ji
The pyrolysis of rice straw as a feedstock in molten carbonates pyrolysis (MCP) and electrochemically assisted molten carbonates pyrolysis (EMCP) systems was investigated in this study. Molten carbonates (MC) were utilized as both the heat transfer medium and the electrolyte in EMCP. The results suggested that EMCP helped to reduce the formation of tar and water, while promoting the formation of gases, especially CO 2 . The optimum reaction conditions were 600 mA/cm 2 of current density in a particle size of 3 mm at 550 °C, with the maximum H 2 and CH 4 yields of 0.26 mol/100 g and 0.17 mol/100 g, and the yield of hydrocarbons peaked at 5.0%. EMCP system reinforced the reaction by accelerating the reaction rate rather than reducing the activation energy. The electrochemical process facilitated the conversion of the hydroxyl groups and a fraction of the carbonyl groups in the biomass to carboxyl groups, which then underwent decarboxylation to release CO 2 in the MC medium. Because oxygen atoms were removed from the system as CO 2 , the water formation decreased. The EMCP system showed benefits in the synthesis of hydrogen and hydrocarbons, and opened a novel pathway for the deoxygenation of biomass in pyrolysis.
Wenbo Sui,Wangzu Li,Zhongshuo Zhang,Weixing Wu,Zhanyou Xu,Ying Wang
Electrochemical synthesis of hydrogen peroxide (H 2 O 2 ) through 2-electron oxygen reduction reaction (ORR) is a sustainable alternative to the industrialized anthraquinone oxidation process . Gas-diffusion electrode (GDE) is employed to overcome the mass transport limitation of O 2 to deliver high current density . However, long-term stability in practical electrolyzer with GDE is still challenging due to electrode flooding. Here, we propose a double catalyst layer (CL) strategy with gradient Nafion distribution to balance the mass transport of O 2 and H + and improve the flood-proof ability. Our design achieved H 2 O 2 production rate up to 2.16 mmol h −1 cm −2 with a selectivity of about 90% and enabled 48 h stable electrolysis at 100 mA cm −2 . Compared to the state-of-the-art H 2 O 2 electrosynthesis system in acidic media, the full-cell voltage improved significantly to 2.3 V at 100 mA cm −2 , indicating its potential for practical production and utilization.
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