Understanding the mechanism of two-step, pyrolysis-alkali chemical activation of fibrous biomass for the production of activated carbon fibre matting

Improving Fresh and End-Used Carbon Surface by Sunlight: A Step Forward in Sustainable Carbon Processing

“…The heat from the focused sunlight releases the residual moisture from the carbon materials, generating a vapor-filled atmosphere identical to that of steam activation. The vapor would then interact with the surface carbon, forming hydroxide surface functional group. , This is in line with the observation of the increasing presence of the −OH deconvoluted peak from the XPS analysis (Figure b). On the other hand, the residual oxygen would interact with the surface carbon, forming oxygenated surface functional group.…”

Chemically Activated Spruce Organosolv Lignin as a Carbocatalyst for Heterogeneous Oxidative Dehydrogenations in the Liquid Phase

“…The high amount of oxygen in the materials obtained at 700 °C is presumably related to this stage of the process. At higher T and KOH loading, these groups start to be eroded, increasing the surface area and lowering the O content …”

“…We selected KOH as the activating agent because its mechanism of action has been studied thoroughly: by reviewing the literature on the topic, the temperature and the ratio between the chemical agent and lignin were selected as the most influential parameters for tuning the development of porosity in the generated active carbons . The temperature treatment was conducted between 700 and 900 °C: as reported in a recent study, in fact, at temperatures higher than 700 °C, the micropores initially formed at lower temperatures (350–400 °C) start to widen, leading to the formation of larger ones, with the anticipated advantage of facilitating reagent diffusion during liquid phase catalysis. One-stage pyrolysis, without pre-carbonization, was preferred as it reduces the preparation steps and the overall environmental impact and economic cost and has been reported to produce a better porous structure .…”

Current approaches, emerging developments and functional prospects for lignin-based catalysts – a review

“…54,178 Considerably, chemicals including KOH, NaOH, K 2 CO 3 , Na 2 CO 3 , Ba(OH) 2 and KCl are the most commonly utilized activators for such applications that can lead to well-established porous materials with high BET surfaces. [181][182][183] The base activation involves the impregnation of lignin in KOH, NaOH, etc. with a certain ratio and subsequent pyrolysis at high temperatures.…”

“…54,184 Interestingly, the performances of these activation approaches can be significantly impacted by the type of activator, the lignin/activator ratio, the temperature and the processing time. 54,[181][182][183]185 Although this activation of lignin can provide high-porous carbon materials, it is necessary to introduce further functionalization for their catalytic implementation given the insufficient availability of active sites. In this respect, grafting additional functional reactive sites onto the surface of lignin-derived carbon is considered to be a key strategy for the development of these types of lignin-derived catalysts.…”