查看更多>>摘要：Thermocatalytic CO2 hydrogenation to methanol is an attractive defossilization technology to combat climate change while producing a valuable platform chemical and energy carrier. However, predicting the performance of catalytic systems for this process remains a challenge. Herein, we present a machine learning framework to predict catalyst performance from experimental descriptors. A database of Cu-, Pd-, In2O3-, and ZnO-ZrO2-based catalysts with 1425 datapoints is compiled from literature and subjected to data mining. Accurate ensemble-tree models (R2 > 0.85) are developed to predict the methanol space-time yield (STY) from 12 descriptors, where the significance of space velocity, pressure, and metal content is revealed. The model prediction and its insights are experimentally validated, with a root mean squared error of 0.11 gMeOH h-1 gcat dicted methanol STY. The framework is purely data-driven, interpretable, cross-deployable to other catalytic processes, and serves as an invaluable tool for guided experiments and optimization.
查看更多>>摘要：Iron oxyhydroxide (FeOOH) as the real active species of Fe-based electrocatalysts holds great promise in industrial water electrolysis. However, the poor conductivity and OER kinetics hinder its catalytic performance. Herein, we have developed a facile dynamic anion regulation strategy to enhance OER activity of FeOOH. Of the seven common anions (VO33-, MoO42-, WO42-, S2-, H2PO4- , H2PO2- and F-), S2- was found to have the best regulatory effect. The obtained 0.01 S-FeOOH+1000/IF exhibits industrial-level OER current output of 1000 mA cm-2 with low overpotential of 358 mV. Importantly, this catalyst can operate stably at 1000 mA cm-2 for at least 1000 h. Theoretical calculation reveals that the doping of sulfur can drastically lower the energy barrier of ratedetermining step during OER. Meanwhile, 0.01 S-FeOOH+1000/IF in alkaline anion exchange membrane (AEM) cells demonstrates a stable cell voltage of 2.12 V to reach 1000 mA cm-2 over 24 h.
查看更多>>摘要：Direct conversion of CO2 and CH4 into value-added oxygenates under mild conditions is highly desirable since it has great potential to deliver a sustainable low-carbon economy and a carbon-neutral ecosystem. However, tuning the distribution of oxygenates in this process remains a major challenge. Here, the electronic structure and acidic properties of copper-based catalysts were exploited as strategies to tune the distribution of oxygenates (alcohols and acids) in the plasma-catalytic conversion of CO2 and CH4 at a reaction temperature of 60 degrees C and atmospheric pressure. We use support, on which copper is anchored, to regulate the distribution of Cu2+ and Cu+ in the Cu-based catalysts. Comprehensive characterization of the catalysts together with the reaction performances reveals that Cu2+ species are favorable to the formation of alcohols, whereas Cu+ species are critical to enhancing acetic acid production. Furthermore, the Brunsted acid sites of HZSM-5 significantly improved the selectivity of acetic acid, while the synergy of isolated Cu+ center and Brunsted acid sites, developed via Cu-exchange HZSM-5, exhibits potential for acetic acid formation. Finally, possible pathways for the formation of alcohols and acetic acid have been discussed. This work provides new insights into the design of highly selective catalysts for tuning the distribution of alcohols and acids in the plasma-catalytic conversion of CO2 and CH4 to oxygenates.
查看更多>>摘要：Highly effective electrocatalysts are of vital importance for advanced applications. Here we show that fully pi-conjugated dense topological salophen organic frameworks with atomic dispersed tetradentate cobalt sites insitu growth on Kejtenblack are high-efficiency and durable electrocatalyst for the oxygen reduction, with a remarkable half-wave potential of 0.959 V which surpassing that of benchmark Pt/C catalyst, and is among the highest of reported single atom electrocatalysts. The electron transfer number was 3.92-3.99 and the yield of peroxide remains below 4% in 0.40-0.95 V. When employed as a cathode electrocatalyst for zinc-air batteries, it showed a high open-circuit voltage (1.5558 V) and maximum power density (178 mWcm(-2)) and high specific capacity (804 mAhg(zn)(-1)). The work reported here revealed that tailoring the active centers, conjugated structures, building blocks and topologies at atomic level could synergistically enhance the ORR activity which are highly valuable for zinc-air batteries and fuel cells.
NSTL
Elsevier