Search

Chemistry, a vital tool for sustainable development, faces a challenge due to the lack of clear guidance on actionable steps, hindering the optimal adoption of sustainability practices across its diverse facets from discovery to implementation. This Scientific Perspective explores established frameworks and principles, proposing a conciliated set of triple E priorities anchored on Environmental, Economic, and Equity pillars for research and decision making. We outline associated metrics, crucial for quantifying impacts, classifying them according to their focus areas and scales tackled. Emphasizing catalysis as a key driver of sustainable synthesis of chemicals and materials, we exemplify how triple E priorities can practically guide the development and implementation of processes from renewables conversions to complex customized products. We summarize by proposing a roadmap for the community aimed at raising awareness, fostering academia–industry collaboration, and stimulating further advances in sustainable chemical technologies across their broad scope. [ABSTRACT FROM AUTHOR]

Decarbonizing the chemical industry will eventually entail using CO2 as a feedstock for chemical synthesis. However, many chemical syntheses involve CO2 reduction using inputs such as renewable hydrogen. In this review, chemical processes are discussed that use CO2 as an oxidant for upgrading hydrocarbon feedstocks. The captured CO2 is inherently reduced by the hydrocarbon co‐reactants without consuming molecular hydrogen or renewable electricity. This CO2 utilization approach can be potentially applied to synthesize eight emission‐intensive molecules, including olefins and epoxides. Catalytic systems and reactor concepts are discussed that can overcome practical challenges, such as thermodynamic limitations, over‐oxidation, coking, and heat management. Under the best‐case scenario, these hydrogen‐free CO2 reduction processes have a combined CO2 abatement potential of approximately 1 gigatons per year and avoid the consumption of 1.24 PWh renewable electricity, based on current market demand and supply. [ABSTRACT FROM AUTHOR]

The electroreduction of carbon dioxide using renewable electricity is an appealing strategy for the sustainable synthesis of chemicals and fuels. Extensive research has focused on the production of ethylene, ethanol and n‐propanol, but more complex C4 molecules have been scarcely reported. Herein, we report the first direct electroreduction of CO2 to 1‐butanol in alkaline electrolyte on Cu gas diffusion electrodes (Faradaic efficiency=0.056 %, j1‐Butanol=−0.080 mA cm−2 at −0.48 V vs. RHE) and elucidate its formation mechanism. Electrolysis of possible molecular intermediates, coupled with density functional theory, led us to propose that CO2 first electroreduces to acetaldehyde‐a key C2 intermediate to 1‐butanol. Acetaldehyde then undergoes a base‐catalyzed aldol condensation to give crotonaldehyde via electrochemical promotion by the catalyst surface. Crotonaldehyde is subsequently electroreduced to butanal, and then to 1‐butanol. In a broad context, our results point to the relevance of coupling chemical and electrochemical processes for the synthesis of higher molecular weight products from CO2. [ABSTRACT FROM AUTHOR]

Optimal amounts of CO2 are added to syngas to boost the methanol synthesis rate on Cu-ZnO-Al2O3 in the industrial process. The reason for CO2 promotion is not sufficiently understood at the particle level due to the catalyst complexity and the high demands of characterization under true reaction conditions. Herein, we applied operando synchrotron X-ray powder diffraction and modulated-excitation infrared spectroscopy on a commercial catalyst to gain insights into its morphology and surface chemistry. These studies unveiled that Cu and ZnO agglomerate and ZnO particles flatten under CO/H2 and/or CO2/H2. Under the optimal CO/CO2/H2 mixture, sintering is prevented and ZnO crystals adopt an elongated shape due to the minimal presence of the H2O byproduct, enhancing the water-gas shift activity and thus the methanol production. Our results provide a rationale to the CO2 promotion emphasizing the importance of advanced analytical methods to establish structure-performance relations in heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Methanol synthesis by CO2 hydrogenation is attractive in view of avoiding the environmental implications associated with the production of the traditional syngas feedstock and mitigating global warming. However, there still is a lack of efficient catalysts for such alternative processes. Herein, we unveil the high activity, 100 % selectivity, and remarkable stability for 1000 h on stream of In2O3 supported on ZrO2 under industrially relevant conditions. This strongly contrasts to the benchmark Cu-ZnO-Al2O3 catalyst, which is unselective and experiences rapid deactivation. In-depth characterization of the In2O3-based materials points towards a mechanism rooted in the creation and annihilation of oxygen vacancies as active sites, whose amount can be modulated in situ by co-feeding CO and boosted through electronic interactions with the zirconia carrier. These results constitute a promising basis for the design of a prospective technology for sustainable methanol production. [ABSTRACT FROM AUTHOR]

A literature survey reveals a prominent reduction in the concentration of Brønsted acid sites in hierarchically organized zeolites with increasing mesoporous or external surface area independent of the framework type or synthesis route; this suggests a common fundamental explanation. To determine the cause, nature, and impact of the underlying changes in aluminum speciation, this study combines a multitechnique analysis that integrates basic characterization, a detailed synchrotron XRD and multiple-quantum NMR spectroscopy assessment, and catalytic tests to correlate evolution of the properties with performance during successive steps in the preparation of hierarchical MFI-type zeolites by desilication. The findings, subsequently generalized to FAU- and BEA-type materials, identify the crucial impact of calcination on the protonic form, which is an integral step in the synthesis and regeneration of zeolite catalysts; on aluminum coordination; and the associated acidity trends. [ABSTRACT FROM AUTHOR]

The article discusses the unique stability of delafossite copper chromium oxide (CuCrO2) during oxidation and chlorination. It presents a novel CuCrO2-cerium oxide (CeO2 composite for hydrogen chloride (HCl) oxidation to build on the result with fourfold activity. It states that in an equimolar mixture of copper oxide (Cu2O), single-phase cuprous delafossites were synthesized at 1273-1423 Kelvin (K) for 30 hours.

Cover Feature: Synthesizing High-Volume Chemicals from CO2 without Direct H2 Input (ChemSusChem 23/2020) Keywords: carbon capture and utilization; C-C coupling; dry reforming; heterogeneous catalysis; oxidative dehydrogenation EN carbon capture and utilization C-C coupling dry reforming heterogeneous catalysis oxidative dehydrogenation 6049 6049 1 12/09/20 20201207 NES 201207 B The Cover Feature b shows a decoupling of CO SB 2 sb utilization from the H SB 2 sb economy. Carbon capture and utilization, C-C coupling, dry reforming, heterogeneous catalysis, oxidative dehydrogenation. [Extracted from the article]

It takes two to tango The production of the energy carrier and platform chemical methanol by CO2 hydrogenation is expected to become a key step in a sustainable economy but the realization of this process requires high‐performance catalysts. In their Communication on page 6261 ff., J. Pérez‐Ramírez and co‐workers demonstrate that the synergistic interaction of In2O3 and a ZrO2 carrier leads to a highly stable material that provides methanol in high space time yields and with almost 100 % selectivity. [ABSTRACT FROM AUTHOR]

The evolutionary tale of palladium‐based catalysts for selective alkyne hydrogenation, from bare to lead‐alloyed, and, most recently, ligand‐modified nanoparticles, is unlocked using flow chemistry. Distinctions in the performance of each catalyst system as well as accessibility constraints arising from the use of ligands are identified and rationalized. For more details, see the Full Paper by J. Pérez‐Ramírez, N. López et al. on page 5926 ff. [ABSTRACT FROM AUTHOR]