Covalent organic frameworks (COFs) are crystalline, highly porous, two- or three-dimensional polymers with tunable topology and functionalities. Because of their higher chemical stabilities in comparison to their boron-linked counterparts, imine or β-ketoenamine linked COFs have been utilized for a broad range of applications, including gas storage, heterogeneous catalysis, energy storage devices, or proton-conductive membranes. Herein, we report the synthesis of highly porous and chemically stable acetylene (-C≡C-) and diacetylene (-C≡C-C≡C-) functionalized β-ketoenamine COFs, which have been applied as photocatalyst for hydrogen generation from water. It is shown that the diacetylene moieties have a profound effect as the diacetylene-based COF largely outperforms the acetylene-based COF in terms of photocatalytic activity. As a combined effect of high porosity, easily accessible diacetylene (-C≡C-C≡C-) functionalities and considerable chemical stability, an efficient and recyclable heterogeneous photocatalytic hydrogen generation is achieved.

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The influence of the support material of vanadia catalysts on the reaction rate, activation energies, and defect formation enthalpies was investigated for the oxidative dehydrogenation of ethanol and propane. Characterization by infrared absorption–reflection spectroscopy (IRAS), Raman and UV–vis spectroscopy verifies a high dispersion of vanadia for powder and thin-film model catalysts. The support effect of ceria, alumina, titania, and zirconia is reflected in activation energy, oxidative dehydrogenation (ODH) rate, and temperature-programmed reductions (TPR) for both catalyst systems, ethanol and propane. Impendence spectroscopy and density functional theory (DFT) calculations were used to determine the defect formation enthalpy of the vanadyl oxygen double bond, providing the scaling parameter for a Bell–Evans–Polanyi relationship. On the basis of a Mars–van-Krevelen mechanism, an energy profile for the oxidative dehydrogenation is proposed

Covalent organic frameworks (COFs) have emerged as an important class of organic semiconductors and photocatalysts for the hydrogen evolution reaction (HER)from water.T oo ptimize their photocatalytic activity,t ypically the organic moieties constituting the frameworks are considered and the most suitable combinations of them are searched for. However,t he effect of the covalent linkage between these moieties on the photocatalytic performance has rarely been studied. Herein, we demonstrate that donor-acceptor (D-A) type imine-linked COFs can produce hydrogen with ar ate as high as 20.7 mmol g À1 h À1 under visible light irradiation, upon protonation of their imine linkages.Asignificant red-shift in light absorbance,largely improved charge separation efficiency,a nd an increase in hydrophilicity triggered by protonation of the Schiff-base moieties in the imine-linked COFs,a re responsible for the improved photocatalytic performance.

A fast and facile route for the optimization of covalent triazine frameworks (CTFs) for photocatalytic hydrogen production is presented. Within 10 minutes a CTF with low photocatalytic activity can be converted into a highly active photocatalyst. Optimized CTF catalysts show an average hydrogen evolution rate of 1072 μmol h g under visible light (>420 nm).

The intended audience for this document are practitioners that want to learn how to create comprehensible and consistent techno-economic assessments and life cycle assessments in the CCU field. These practitioners may come from academia, industry or government and may work in technology assessment and technology research and development, or funding, they may be part of the CCU community, the TEA community or the LCA community. Readers of TEA and LCA, such as investors, policy Part A: General Assessment Principles Part B: TEA guidelines Part C: LCA guidelines PART A: GENERAL ASSESSMENT PRINCIPLES TEA & LCA Guidelines for CO2 Utilization 8makers or funding decision makers are not the intended audience for these TEA and LCA guidelines, but may use this document to understand the challenges and pitfalls for TEA and LCA. A.2.4 Limitations of this documentThese guidelines have been developed to enable consistent and comparable LCA and TEA studies for CCU. They are not intended to serve as an assessment standard or rulebook. Instead they are meant to help practitioners to conduct sound assessments efficiently, avoid common mistakes and to derive meaningful results that can be compared to other studies. This document serves as an addition to conventional existing standards (in particular for LCA) and literature and does not replace any chemical engineering, economics or project planning principles. However, since the guidelines aim to enhance the comparability and transparency of studies, the LCA guidelines are more restrictive than the general ISO-framework. In some cases, there may be need to add further tasks to the ones discussed in this guideline since they are important to a specific study. Such additions are not excluded by the present guideline. However, the guidelines provide a consistent methodological core for conducting all LCA and TEA CCU studies.This document is intended as the first step of a longer framework development process. TEA and LCA remain two separate approaches in this document as is common in current assessment practice in academic literature and industry. However, a combined approach is in strong demand to include trade-offs in decision making. The integration of TEA and LCA into one singular study is a next major development step that is subject to future work. This document provides some initial guidance to those who wish to carry out an integrated TEA & LCA study, however many facets of the integration process are still to be determined. A.2.5 The guidelinesThe guidelines for TEA are presented in part B of this document and LCA in part C. At the end of each guideline chapter there is a box listing rules that these guidelines recommend. The box contains three categories, shall, should and may:TEA & LCA Guidelines for CO2 Utilization 9TEA & LCA Guidelines for CO2 Utilization 14 A.4.2.4 GuidelinesGuideline A.1 -Technology maturity Shall 1) Technology maturity shall be defined in each assessment -first for each system element and second for the overall product system 2) The maturity of the over...