The potential of on-purpose ethylene production, in parallel with CO 2 conversion to CO, is of great interest. Iron oxide-based catalysts supported on mixed oxides zNiOÀ MgOÀ ZrO 2 , z = 0-10 wt%, are active for the CO 2 -assisted oxidative dehydrogenation of ethane at 873 K and 101.3 kPa. Enhanced control of their selectivity towards CÀ H bond cleavage and not towards CÀ C bond cleavage can be achieved by adjusting the Ni/Fe ratio. Fine tuning Ni/Fe molar ratio results in stable catalytic performance, with selectivity towards C 2 H 4 > 65 % and C 2 H 6 conversion > 20 %. Density functional theory (DFT) calculations show a significant enhancement in activity due to decrease in the oxygen-vacancy formation energy and the increase in hydrogen adsorption energy at the Ni oxide-Fe oxide interface. The latter interface is the potential active site responsible for the enhanced performance that was experimentally exemplified for the Fe oxide/zNiOÀ MgOÀ ZrO 2 catalysts vs Fe oxide/

Numerous hyper-cross-linked polymers (HCPs) have been developed as CO 2 adsorbents and photocatalysts. Yet, little is known of the CO 2 and H 2 O adsorption mechanisms on amorphous porous polymers. Gaining a better understanding of these mechanisms and determining the adsorption sites are key to the rational design of improved adsorbents and photocatalysts. Herein, we present a unique approach that combines density functional theory (DFT), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and multivariate spectral analysis to investigate CO 2 and H 2 O adsorption sites on a triazine−biphenyl HCP. We found that CO 2 and H 2 O adsorb on the same HCP sites albeit with different adsorption strengths. The primary amines of the triazines were identified as favoring strong CO 2 binding interactions. Given the potential use of HCPs for CO 2 photoreduction, we also investigated CO 2 and H 2 O adsorption under transient light irradiation. Under irradiation, we observed partial CO 2 and H 2 O desorption and a redistribution of interactions between the H 2 O and CO 2 molecules that remain adsorbed at HCP adsorption sites.

Conspectus The research of new porous materials for applications in interfacial processes is key to addressing global energy and sustainability challenges. For example, porous materials can be used to store fuels such as hydrogen or methane or to separate chemical mixtures reducing the energy currently required by thermal separation processes. Their catalytic properties can be exploited to convert adsorbed molecules into valuable or less hazardous chemicals, thereby reducing energy consumption or pollutants emissions. Porous boron nitride (BN) has appeared as a promising material for applications in molecular separations, gas storage, and catalysis owing to its high surface area and thermal stability, as well as its tunable physical properties and chemistry. However, the production of porous BN is still limited to the laboratory scale, and its formation mechanism, as well as ways to control porosity and chemistry, are yet to be fully understood. In addition, studies have pointed toward the instability of porous BN materials when exposed to humidity, which could significantly impact performance in industrial applications. Studies on porous BN performance and recyclability when employed in adsorption, gas storage, and catalysis remain limited, despite encouraging preliminary studies. Moreover, porous BN powder must be shaped into macrostructures (e.g., pellets) to be used commercially. However, common methods to shape porous materials into macrostructures often cause a reduction in the surface area and/or mechanical strength. In recent years, research groups, including ours, have started addressing the challenges discussed above. Herein, we summarize our collective findings through a selection of key studies. First, we discuss the chemistry and structure of BN, clarifying confusion around terminology and discussing the hydrolytic instability of the material in relation to its structure and chemistry. We demonstrate a way to reduce the instability in water while still maintaining high specific surface area. We propose a mechanism for the formation of porous BN and discuss the effects of different synthesis parameters on the structure and chemistry of porous BN, therefore providing a way to tune its properties for selected applications. While the syntheses covered often lead to a powder product, we also present ways to shape porous BN powders into macrostructures while still maintaining high accessible surface area for interfacial processes. Finally, we evaluate porous BN performance for chemical separations, gas storage, and catalysis. While the above highlights key advances in the field, further work is needed to allow deployment of porous BN. Specifically, we suggest evaluating its hydrolytic stability, refining the ways to shape the material into stable and reproducible macrostructures, establishing clear design rules to produce BN with specific chemistry and porosity, and, finally, providing standardized test procedures to evaluate porous BN catalytic and sorp...