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Metrics & MoreArticle Recommendations CONSPECTUS: CO 2 conversion to valuable chemicals is effective at reducing CO 2 emissions. We previously proposed valorization strategies and developed efficient catalysts to address thermodynamic stability and kinetic inertness issues related to CO 2 conversion. Earlier, we developed molecular capture reagents and catalysts to integrate CO 2 capture and conversion, i.e., in situ transformation. Based on the mechanistic understanding of CO 2 capture, activation, and transformation at a molecular level, we set out to develop heterogeneous catalysts by incorporating catalytic units into nanomaterials via the immobilization of active molecular catalysts onto nanomaterials and designing nanomaterials with intrinsic catalytic sites.In thermocatalytic CO 2 conversion, carbonaceous and metal−organic framework (MOF)based catalysts were developed for nonreductive and reductive CO 2 conversion. Novel Cu-and Zn-based MOFs and carbon-supported Cu catalysts were prepared and successfully applied to the cycloaddition, carboxylation, and carboxylative cyclization reactions with CO 2 , generating cyclic carbonates, carboxyl acids, and oxazolidinones as respective target products. Reductive conversion of CO 2 , especially reductive functionalization with CO 2 , is a promising transformation strategy to produce valuable chemicals, alleviating chemical production that relies on petrochemistry. We explored the hierarchical reductive functionalization of CO 2 using organocatalysts and proposed strategies to regulate the CO 2 reduction level, triggering heterogeneous catalyst investigation. Introducing multiple active sites into nanomaterials opens possibilities to develop novel CO 2 transformation strategies. CO 2 capture and in situ conversion were realized with an N-doped carbon-supported Zn complex and MOF materials as CO 2 adsorbents and catalysts. These nanomaterial-based catalysts feature high stability and excellent efficiency and act as shape-selective catalysts in some cases due to their unique pore structure. Nanomaterial-based catalysts are also appealing candidates for photocatalytic CO 2 reduction (PCO 2 RR) and electrocatalytic CO 2 reduction (ECO 2 RR), so we developed a series of hybrid photo-/electrocatalysts by incorporating active metal complexes into different matrixes such as porous organic polymers (POPs), metal−organic layers (MOLs), micelles, and conducting polymers. By introducing Re-bipyridine and Fe-porphyrin complexes into POPs and regulating the structure of the polymer chain, catalyst stability and efficiency increased in PCO 2 RR. PCO 2 RR in aqueous solution was realized by designing the Re-bipyridine-containing amphiphilic polymer to form micelles in aqueous solution and act as nanoreactors. We prepared MOLs with two different metallic centers, i.e., the Ni-bipyridine site and Ni-O node, to improve the efficiency for PCO 2 RR due to the synergistic effect of these metal centers. Sulfylphenoxy-decorated cobalt phthalocyanine (CoPc) cross-linked polypyrrole was prep...

Carbon dioxide (CO2) is the major greenhouse gas and also an abundant and renewable carbon resource. Therefore, its chemical conversion and utilization are of great attraction for sustainable development. Especially, reductive conversion of CO2 with energy input has become a current hotspot due to its ability to access fuels and various important chemicals. Nowadays, the controllable CO2 hydrogenation to formic acid and alcohols using sustainable H2 resources has been regarded as an appealing solution to hydrogen storage and CO2 accumulation. In addition, photocatalytic CO2 reduction to CO also provides a potential way to utilize this greenhouse gas efficiently. Besides direct CO2 hydrogenation, CO2 reductive functionalization integrates CO2 reduction with subsequent C–X (X = N, S, C, O) bond formation and indirect transformation strategies, enlarging the diverse products derived from CO2 and promoting CO2 reductive conversion into a new stage. In this Perspective, the progress and challenges of CO2 reductive conversion, including hydrogenation, reductive functionalization, photocatalytic reduction, and photocatalytic reductive functionalization are summarized and discussed along with the key issues and future trends/directions in this field. We hope this Perspective can evoke intense interest and inspire much innovation in the promise of CO2 valorization.

Biomass‐based polymers and their property regulation using functional materials have attracted much interest. In this work, ricinoleic acid‐derived cyclic carbonate was prepared and applied to the synthesis of nonisocyanate polyurethane (NIPU) with aliphatic diamine, in which octa(aminopropyl) polyhedral oligomeric silsesquioxane (OAP‐POSS) was incorporated as polyamine to partially or totally substitutes for the diamine to introduce POSS units into the polymer thus regulating the properties of the resultant material. In the curing process, Fourier transform infrared spectroscopy (FT‐IR) was used to track the reaction and curing at 50°C for 12 h was found to be sufficient for the polymerization. A series of POSS modified NIPUs were obtained by altering the molar fraction of OAP‐POSS in total amine components and the material with the highest thermal stability, shore hardness and water resistance was accessed with 100% substitution of OAP‐POSS for diamine.

The extraction of rolling bearings’ degradation features has been developed for decades. However, the degradation features always present different trends of different run-to-failure data. To find a consistent indicator of different data will be helpful to establish a general model and explore the nature of bearings’ degradation. In this study, we have found there is a trend of similarity between the energy and complexity features. By using the cointegration test, we found the two kinds of features exhibit a certain degree of cointegration relationship. Fused by the cointegration method, we have obtained a novel health indicator which can depict different run-to-failure data in a unified way. The difference between the energy features and complexity features can be explained by the novel health indicator. The indicator has “two-stage” characters. The first stage is the zero-line stage and the second stage is the quickly raise stage, which presents like an exponential function. It is easy to think about using an exponential degradation model to model this indicator. Next, we have compared the indicator to root mean square (RMS) by using the exponential degradation model. It shows that the indicator is more suitable for the exponential degradation model. In this paper, we used eleven run-to-failure data to verify the generality and “two-stage” characters of the proposed indicator. The result shows that the novel indicator is general and effective and that it will promote the development of bearings’ prognostics.