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Palladium (Pd) nanostructures are highly active non-platinum anodic electrocatalysts in alkaline direct methanol fuel cells (DMFCs), and their electrocatalytic performance relies highly on their morphology and composition. This study reports the preparation, characterizations, and electrocatalytic properties of palladium-copper alloys loaded on the carbon support. XC-72 was used as a support, and hydrazine hydrate served as a reducing agent. PdxCuy/XC-72 nanoalloy catalysts were prepared in a one-step chemical reduction process with different ratios of Pd and Cu. A range of analytical techniques was used to characterize the microstructure and electronic properties of the catalysts, including transmission electron microscopy (TEM), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma emission spectroscopy (ICP-OES). Benefiting from excellent electronic structure, Pd3Cu2/XC-72 achieves higher mass activity enhancement and improves durability for MOR. Considering the simple synthesis, excellent activity, and long-term stability, PdxCuy/XC-72 anodic electrocatalysts will be highly promising in alkaline DMFCs. [ABSTRACT FROM AUTHOR]

HZSM-5@silicalite-1 catalysts were prepared by the hydrothermal method, and the structure, morphology, acidity and pore texture of core–shell catalysts were studied by XRD, SEM, TEM, NH3-TPD, Py-IR and N2 adsorption/desorption isotherms in detail. Their catalytic performances were tested in the alkylation reaction of toluene with methanol. The results showed that a coating layer was formed in the form of silicalite-1 on HZSM-5. NH3-TPD measurements indicated that HZSM-5@silicalite-1 contained less strong acid sites but more weak acid sites than the parent HZSM-5. The selectivity of p-xylene for toluene alkylation was approximately linear with the percentage of weak acid in total acid. Under the optimal reaction conditions, the conversion of toluene was 34.15%, and the selectivity of p-xylene was 96.77%. [ABSTRACT FROM AUTHOR]

The preparation of aromatic by methanol was the most effective way for rational utilization of resources. However, the catalyst for MTA reaction has not yet been successfully studied. Therefore, highly active and shape‐selective HZSM‐5 zeolite‐based catalysts were designed and synthesized by post‐treatments of desilication, dealumination, surface‐passivation and hydrothermal treatment tuning pore structure and acid amount and acid concentration of catalysts. XRD, SEM, TEM, BET, NH3‐TPD and Py‐IR were used for research and analysis the structure‐activity relationship between the catalysts and MTA reaction. The results showed that the total acid amount of catalyst shown a significant role in increasing the BTX selectivity. The selectivity of aromatics increased from 33 % to 58.1 % after hydrothermal treatment compared to the parent HZSM‐5 zeolite due to the decreased of total acid amount. Nevertheless the weak acid sites were crucial in increasing the p‐xylene selectivity. The selectivity of p‐xylene reached 63.8 % and 70.1 % after hydrothermal treatment and surface‐passivation due to the increased of weak acid sites, respectively. Modified HZSM‐5 zeolite‐base catalysts showed good application prospects in producing aromatics from methanol. [ABSTRACT FROM AUTHOR]

• Indirect and direct electrification of coal-to-methanol process are investigated. • Energy efficiency of the semi-electrification scenario reaches to 64.31 %. • Semi-electrification scenario achieves the minimum CO 2 emissions. • Total production cost of semi-electrification scenario is 301.0 $/t and a payback time of 4.13 years. • Fully-electrification scenario is not an ideal choice from comprehensive performances comparison. Electrification of traditional large-scale chemical industry based on renewable electricity can greatly reduce process CO 2 emission, and store intermittent renewable electricity into chemical products locally to decrease power grid frequency regulation caused by fluctuating renewable electricity. This study presents a framework for electrification of chemical industry from indirect and direct aspects using the state-of-art coal-to-methanol process as a case study. Traditional coal-to-methanol (Process 1) suffers from high CO 2 emission due to mismatch of H/C ratio between coal and methanol. A pulverized coal gasification-integrated SOEC process (Process 2) has been investigated, the water–gas-shift unit is avoided and a simplified acid gas removal process is implemented to replace traditional acid gas removal unit in Process 2. Electric heaters and heat pump system are applied in Process 2 as direct electrification methods to form semi-electrified scenario (Process 3). To discuss the effect of electrification levels on process performances, a fully electrified process (Process 4) is also designed. The results show that: CO 2 emissions of the four processes are 2.19, 0.71, 0.52 and 0.63 t/t MeOH, and energy efficiency are 57.40 %, 62.32 %, 64.31 % and 57.63 %, respectively. Production costs are 159.1, 294.3, 301.0 and 358.3 $/t MeOH, IRRs are 14, 31, 29 and 14.5 %, respectively. Through this research and analysis, we hope to explore integration potential of renewable electricity and traditional chemical industry, and design a greener methanol production route based on renewable electricity. [ABSTRACT FROM AUTHOR]

Carbon dioxide hydrogenation to produce methanol has the potential to liberate humanity from its reliance on fossil fuels, while simultaneously reducing carbon dioxide and developing the economy. This paper focuses on the effect of catalyst type and the process conditions such as temperature, pressure, H 2 /CO 2 feed ratio, and space velocity on CO 2 conversion and CH 3 OH selectivity. The net generated CO in the reaction system results in the loss of CO 2 and H 2 to the purge gas, which reduces the utilization efficiency of carbon and hydrogen. The specially designed catalysts and processes with recycling can improve CO 2 conversion and CH 3 OH selectivity, and the CO flow rate difference can be close to zero in the total recycling condition. Starting from these ideas, the two kinds of near-zero carbon emission processes with total recycling (respectively named total recycling process after flash separation and named total recycling process after stripping separation) are proposed. The utilization efficiency of carbon and hydrogen are similar in the two processes, but hot and cold utilities in the latter are 17.96% and 15.11% lower than in the former, respectively. Through the process integration between reaction heat and double-effect distillation, the energy consumption is further reduced in the total recycling process after stripping separation. The utilization efficiency of CO 2 is 99.88% in the total recycling process after stripping separation with double-effect distillation of the light split/reverse configuration, and the proposed process just requires cold utility. • Proposed a novel CO 2 -to-methanol process with near-zero carbon emission. • Carbon utilization efficiency of the proposed process is 99.88%. • Energy efficiency of the novel process is 90.54%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Models of CTM with different CO 2 capture technologies are built and validated. • Techno-economic and environmental performances of CTM under different CO 2 capture technologies are analyzed and compared. • Low-carbon, efficient, and economically optimal carbon capture technology for green methanol synthesis is explored. • Improvement measures for sustainable development of CTM are proposed. CO 2 -to-methanol can realize the emissions reduction and resource utilization of CO 2. However, CO 2 capture technology will lead to energy and economic penalties of the whole methanol production process. Thus, the effect of different CO 2 capture technologies on the performance of the whole methanol production process is analyzed and compared in this study. A rigorous steady-state modeling and simulation of the four different CO 2 capture technologies (monoethanolamine (MEA), phase-change separation (PCS), dimethyl carbonate (DMC), and gas membrane separation (GMS)) are conducted, and the results are validated with literature data. Accordingly, the technical, economic, and environmental performances of the CO 2 -to-methanol process under different CO 2 capture technologies are analyzed to explore the low-carbon, efficient, and economically optimal carbon capture technology for green methanol synthesis. The results showed that the energy efficiency of the GMS case was the highest (68.4%), followed by PCS (66.2%), DMC (64.3%), and MEA (61.3%). The total production cost of the GMS case was the highest (4367 CNY/t-CH 3 OH), followed by MEA (4314 CNY/t-CH 3 OH), DMC (4279 CNY/t-CH 3 OH), and PCS (4204 CNY/t-CH 3 OH). All four cases achieved CO 2 emissions reductions. With the development of the third generation of biphasic absorbents, the PCS case improved the energy efficiency by 78.6%–83.8%. Thus, the PCS case was the optimal technology choice for achieving low-carbon, efficient, economic trade-offs in the commercial methanol production based on CO 2 capture and utilization. [ABSTRACT FROM AUTHOR]