The conversion of CO2 with CH4 into liquid fuels and chemicals in a single‐step catalytic process that bypasses the production of syngas remains a challenge. In this study, liquid fuels and chemicals (e.g., acetic acid, methanol, ethanol, and formaldehyde) were synthesized in a one‐step process from CO2 and CH4 at room temperature (30 °C) and atmospheric pressure for the first time by using a novel plasma reactor with a water electrode. The total selectivity to oxygenates was approximately 50–60 %, with acetic acid being the major component at 40.2 % selectivity, the highest value reported for acetic acid thus far. Interestingly, the direct plasma synthesis of acetic acid from CH4 and CO2 is an ideal reaction with 100 % atom economy, but it is almost impossible by thermal catalysis owing to the significant thermodynamic barrier. The combination of plasma and catalyst in this process shows great potential for manipulating the distribution of liquid chemical products in a given process.

No abstract

No abstract

A coaxial dielectric barrier discharge (DBD) reactor has been developed for plasma-catalytic conversion of CO2 into value-added chemicals at low temperatures (<150 o C) and atmospheric pressure. The effect of specific energy density (SED) on the performance of the plasma process has been investigated. In the absence of a catalyst in the plasma, the maximum conversion of CO2 reaches 21.7 %. The synergistic effect from the combination of plasma with photocatalysts (BaTiO3 and TiO2) at low temperatures contributes to a significant enhancement of both CO2 conversion and energy efficiency by up to 250%. The synergy of plasma-catalysis for CO2 conversion can be attributed to both the physical effect induced by the presence of catalyst pellets in the discharge and the photocatalytic surface reaction driven by the plasma.

No abstract

Excessive anthropogenic CO2 emission in the atmosphere is considered as one of the main contributions to the serious climate changes. However, with the growth of global economics, more fossil fuels will be consumed to feed the global activity, especially in developing countries. Thus, CO2 needs to be captured for storage or converted to fuels or value-added chemicals. Herein, we propose and demonstrate a one-pot method synthesized dual functional materials (DFMs), which contain a sorbent coupled with a catalyst component, allowing the sorbent regeneration and CO2 conversion to CO to perform simultaneously in a single reactor. This process requires no additional thermal energy for the regeneration of sorbents. In addition, CeO2 is incorporated into the DFMs to largely enhance the stability of the materials for the process, and the influence of different Ce loadings on the performance of integrated CO2 capture and conversion is studied. It is found that the DFMs with a Ca/Ni/Ce molar ratio of 1:0.1:0.033 displays an excellent CO yield (7.24 mmol g -1 ) in the reverse water-gas shift (RWGS) reaction and a remarkable cyclic stability after 20 cycles of integrated CO2 capture and conversion. Therefore, the incorporation of Ce into DFMs has two profits, for one thing, the oxygen vacancies generated by CeO2 directly reduces the dissociated CO2 regenerated from the DFMs, demonstrating the high CO yield; for another, the well-dispersed CeO2, which could act as a physical barrier, effectively prevents the growth and agglomeration of CaO crystallite and NiO species.

Nickel, iron, cobalt and copper catalysts were prepared by impregnation and used to produce carbon nanotubes and hydrogen gas from a LDPE feedstock. A two stage catalytic pyrolysis process was used to enable large yields of both products. Plastics samples were pyrolysed in nitrogen at 600°C, before the evolved gases were passed to a second stage and allowed to deposit carbon onto the catalyst at a temperature of 800°C. Carbon nanotubes were successfully generated on nickel, iron and cobalt but were barely observed on the copper catalyst. Iron and nickel catalysts gave the largest yield of both hydrogen and carbon nanotubes as a result of metal-support interactions which were neither too strong, like cobalts, nor too weak like copper. These metal support interactions proved a key factor in CNT production. A nickel catalyst with a weaker interaction was prepared using a lower calcination temperature. Yields of both carbon nanotubes and hydrogen gas were lower on the Ni-catalyst prepared at the lower calcination temperature, as a result of sintering of the nickel particles. In addition, the catalyst prepared at a lower calcination temperature produced metal particles which were too large for CNT growth, producing amorphous carbons which deactivate the catalyst instead. Overall the iron catalyst gave the largest yield of CNTs, which is attributed to both its good metal-support interactions and irons large carbon solubility.

Recently, carbon dioxide (CO 2 ) conversion into higher-value platform chemicals and synthetic fuels has drawn great attention as a result of global warming. Non-thermal plasma (NTP)-catalytic CO 2 conversion has emerged to significantly reduce the reaction temperature. However, this technology requires a paradigm shift in process design to enhance plasma-catalytic performance. CO 2 conversion using NTP and catalysts has great potential to increase reaction efficiencies due to the synergetic effects between the plasma and catalysts that can provide mutual improvement in their performances. It is crucial to present the recent progress in CO 2 conversion and utilization whilst specifying a research prospects framework and providing future research directions in both industries and laboratories.Herein, a review of encouraging research achievements in CO 2 conversion and utilization using NTP in recent years is provided. The topics reviewed in this work are recent progress in different NTP sources in relation to product selectivity, conversion, and energy efficiency; plasma-based CO 2 reactions and applications; CO 2 conversion integrated with CO 2 capture; and process development of NTP in terms of potential large-scale applications processes. The high market value of the possible products from the NTP process, including chemicals and fuels, make the commercialization of the process feasible. Developing a suitable catalyst with effective sensitivities and performance under intricate conditions can improve the selectivity of these carbon-based liquid chemicals. There is a need for more studies to be performed in this field.