Increasing the activity and selectivity of Co-based FTS catalysts supported by carbon materials for direct synthesis of clean fuels by the addition of chromium

A review of Co/Co2C-based catalysts in Fischer-Tropsch synthesis: from fundamental understanding to industrial applications

Fischer-Tropsch synthesis (FTS), which provides a green route to the production of clean fuels and fine chemicals, represents some significant applications of catalytic materials and processes in the chemical industry. FTS reactions show a diversity of mechanisms, involve various catalytic materials, and offer options for continuous investigation. Cobalt-based catalysts have been widely used for Fischer-Tropsch synthesis both in academia and in industry. This mini-review will focus on relevant research achievements in cobalt-based FTS catalysts by our group in the Dalian Institute of Chemical Physics (DICP). Specific contents will include the development of Co/Co₂C-based nano-catalysts (i) for the highly selective synthesis of clean fuels over Co-based catalysts supported by carbon materials and (ii) for the synthesis of linear α-alcohols and olefins over Co-Co₂C-based catalysts supported by carbon materials. The direct synthesis of linear α-alcohols from syngas using a Co-Co₂C/AC catalyst is highlighted. The innovative work of FTS using activated carbon (AC)-supported Co/Co₂C-based nano-catalysts could bring some insight into new FTS catalyst designs.

Coverage-driven selectivity switch from ethylene to acetate in high-rate CO2/CO electrolysis

Tuning catalyst microenvironments by electrolytes and organic modifications is effective in improving CO₂ electrolysis performance. An alternative way is to use mixed CO/CO₂ feeds from incomplete industrial combustion of fossil fuels, but its effect on catalyst microenvironments has been poorly understood. Here we investigate CO/CO₂ co-electrolysis over CuO nanosheets in an alkaline membrane electrode assembly electrolyser. With increasing CO pressure in the feed, the major product gradually switches from ethylene to acetate, attributed to the increased CO coverage and local pH. Under optimized conditions, the Faradaic efficiency and partial current density of multicarbon products reach 90.0% and 3.1 A cm^-2, corresponding to a carbon selectivity of 100.0% and yield of 75.0%, outperforming thermocatalytic CO hydrogenation. The scale-up demonstration using an electrolyser stack achieves the highest ethylene formation rate of 457.5 ml min^-1 at 150 A and acetate formation rate of 2.97 g min^-1 at 250 A.

N-doped graphitized carbon supported Co@Ru core–shell bimetallic catalyst for hydrogen storage of N-ethylcarbazole

We investigate the hydrogenation of one promising liquid organic hydrogen carrier N-ethylcarbazole on the N-doped graphitized carbon (NGC) supported Co@Ru core–shell bimetallic catalyst.

Fabrication of gelatin microspheres containing ammonium hydrogen carbonate for the tunable release of herbicide

The major challenge in utilizing pesticides lies in identifying the precise application that would improve the efficiency of these pesticides and decline their environmental and health hazards at the same time. Such application requires the development of specific formulations that enable controlled, stimuli-responsive release of the pesticides. Gelatin is a relatively cheap material characterized by temperature-sensitivity and abundant amino acid groups, which makes it suitable for the storage and controlled release of pesticides. In this study, gelatin microspheres were prepared by emulsion and cross-linking, then they were loaded with 2,4-dichlorophenoxyacetic acid sodium (2,4-D Na) as a model herbicide. To achieve temperature-tunable release of 2,4-D Na from the microspheres, NH₄HCO₃ was added to the formulations at different concentrations. The prepared formulations were characterized by SEM, FTIR, and size distribution analyzes, and their drug loading capacities were determined. Based on bioassay experiments, the 2,4-D Na-NH₄HCO₃-loaded gelatin microspheres can effectively control the spread of dicotyledonous weeds. Therefore, the strategy proposed herein can be used to develop novel, effective herbicide formulations.

Carbon-based catalysts for Fischer-Tropsch synthesis

Fischer-Tropsch synthesis (FTS) is an essential approach to convert coal, biomass, and shale gas into fuels and chemicals, such as lower olefins, gasoline, diesel, and so on. In recent years, there has been increasing motivation to deploy FTS at commercial scales which has been boosting the discovery of high performance catalysts. In particular, the importance of support in modulating the activity of metals has been recognized and carbonaceous materials have attracted attention as supports for FTS. In this review, we summarised the substantial progress in the preparation of carbon-based catalysts for FTS by applying activated carbon (AC), carbon nanotubes (CNTs), carbon nanofibers (CNFs), carbon spheres (CSs), and metal-organic frameworks (MOFs) derived carbonaceous materials as supports. A general assessment of carbon-based catalysts for FTS, concerning the support and metal properties, activity and products selectivity, and their interactions is systematically discussed. Finally, current challenges and future trends in the development of carbon-based catalysts for commercial utilization in FTS are proposed.