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With the growing necessity of achieving carbon neutrality in the industrial sector, the catalytic hydrogenation of carbon dioxide into methanol has been widely considered one of the key strategies for the utilization of captured CO 2 . For this reason, the development of alternative catalysts such as ZnZrO x has attracted considerable interest, given its superior stability and versatility in comparison to the conventional Cu-based materials. In this work, ZnZrO x has been produced by a hydrothermal synthesis method at varied synthesis pH between 7 and 10 and a positive association between pH and catalytic CO 2 conversion is observed. At 2.0 MPa and 250 °C, ZnZrO x produced at pH 10 shows a methanol selectivity of 95% at a CO 2 conversion of 3.4%. According to characterization, basic pH conditions enable the formation of abundant t-ZrO 2 and the subsequent incorporation of Zn 2+ into this phase, although the content of surface Zn does not increase between pH 8 and 10. Nevertheless, synthesis pH values can be correlated with surface oxygen content and CO 2 adsorption capacity, which could be important contributors to the higher catalytic activity observed as a result of higher synthesis pH values. However, upon synthesis at pH 10, an inferior selectivity to methanol is observed above 250 °C, as a possible result of the excessive formation of ZnO. Interestingly, this secondary phase can be prevented and the selectivity can be slightly improved by utilizing NH 4 OH instead of NaOH in the hydrothermal method., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Considering the alarming scenario of climate change, CO 2 hydrogenation to methanol is considered a key process for phasing out fossil fuels by means of CO 2 utilization. In this context, MoS 2 catalysts have recently shown to be promising catalysts for this reaction, especially in the presence of abundant basal-plane sulfur vacancies and due to synergistic mechanisms with other phases. In this work, Mn-promoted MoS 2 prepared by a hydrothermal method presents considerable selectivity for CO 2 hydrogenation to methanol in comparison with pure MoS 2 and other promoters such as K and Co. Interestingly, if CO is used as a carbon source for the reaction, methanol production is remarkably lower, which suggests the absence of a CO intermediate during CO 2 hydrogenation to methanol. After optimization of synthesis parameters, a methanol selectivity of 64% is achieved at a CO 2 conversion of 2.8% under 180 °C. According to material characterization by X-ray Diffraction and X-ray Absorption, the Mn promoter is present mainly in the form of MnO and MnCO 3 phases, with the latter undergoing convertion to MnO upon H 2 pretreatment. However, following exposure to reaction conditions, X-ray photoelectron spectroscopy suggests that higher oxidation states of Mn may be present at the surface, suggesting that the improved catalytic activity for CO 2 hydrogenation to methanol arises from a synergy between MoS 2 and MnO x at the catalyst surface., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Carbon and nitrogen are crucial elements for life and must be efficiently regenerated in a circular economy. Biomass streams at the end of their useful life, such as sewage sludge, are difficult to recycle even though they contain organic carbon and nitrogen components. Gasification is an emerging technology to utilize such challenging waste streams and produce syngas that can be further processed into, e.g., Fischer-Tropsch fuels, methane, or methanol. Here, the objective is to investigate if nitrogen can be recovered from product gas cleaning in a dual fluidized bed (DFB) after gasification of softwood pellets to form yeast biomass. Yeast biomass is a protein-rich product, which can be used for food and feed applications. An aqueous solution containing ammonium at a concentration of 66 mM was obtained and by adding other nutrients it enables the growth of the methylotrophic yeast Komagataella phaffii to form 6.2 g.L -1 dry yeast biomass in 3 days. To further integrate the process, it is discussed how methanol can be obtained from syngas by chemical catalysis, which is used as a carbon source for the yeast culture. Furthermore, different gas compositions derived from the gasification of biogenic feedstocks including sewage sludge, bark, and chicken manure are evaluated for their ability to yield methanol and yeast biomass. The different feedstocks are compared based on their potential to yield methanol and ammonia, which are required for the generation of yeast biomass. It was found that the gasification of bark and chicken manure yields a balanced carbon and nitrogen source for the formation of yeast biomass. Overall, a novel integrated process concept based on renewable, biogenic feedstocks is proposed connecting gasification with methanol synthesis to enable the formation of protein-rich yeast biomass., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Shirvani, Bartik, Alves, Garcia de Otazo Hernandez, Müller, Föttinger and Steiger.)

Dielectric-barrier-discharge (DBD) plasma jets provide viable state-of-the-art nonthermal processes for a wide range of nanomaterials including particle transport and deposition. We report the interaction of argon and helium plasma jets with the particle aerosol, produced by ns laser ablation of a silver target and subsequently their transport for deposition on a distant substrate. The nanofeatures and functionality of the nanoparticles, entrained and deposited with the two plasma jets were compared using high-resolution electron microscopy, helium ion microscopy, scanning electron microscopy, ultraviolet-visible spectroscopy, and in terms of the SERS effect. The plasma jet facilitates the transport of the particle aerosol under the upshot of plasma ionic wind, caused by the high electric field in the plasma. Compared to the helium plasma jet, the argon plasma jet leads to a relatively large particle deposition and promotes the formation of aggregates. The helium plasma jet enabled the deposition of spatially well dispersed particles. In both cases, the deposited particle was crystalline and plasmonic active. The plasma-driven altered morphology, expedient particle transport, and formation of agglomerates or spatially well dispersed particles are explained in plasma-induced ionic-wind, and dusty plasma framework. The findings are novel and interesting from the perspective of plasma-surface deposition, surface nanoengineering, and nanomaterial processing for applications in sensing, catalysis, surgical tools, futuristic coating technology, and heat-sensible biological activities., (© 2023. The Author(s).)