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Developing an efficient catalyst to upgrade 5‐hydroxymethylfurfural (HMF) to high‐value‐added downstream chemicals is of great significance in biomass conversion. Nanorod (110)‐, nanocube (100)‐, and nanooctaheron (111)‐CeO2‐supported Au nanoparticles were prepared to investigate the intrinsic effect of CeO2 crystal faces on the oxidation of HMF to 2,5‐furandicarboxylic acid (FDCA). The experimental results and density functional theory calculation revealed that the concentration of oxygen vacancy (VO) for exposed specific crystal faces was crucial to the oxygen adsorption ability, and Au/nanorod‐CeO2 with the highest VO concentration promoted the formation of more oxygen active species (superoxide radical) on CeO2 (110) crystal face than (100) and (111) crystal faces. Besides, the higher VO concentration could provide a strong adsorption ability of HMF, greatly boosting the activation of HMF. Thus, these results led to a superior catalytic activity for HMF oxidation over Au/nanorod‐CeO2 (FDCA yield of 96.5 %). In‐situ Fourier‐transform (FT)IR spectroscopy uncovered the HMF oxidation pathway, and the possible catalytic mechanism was proposed. The deep insight into the role of regulation for crystal faces provides a basis for the rational design of highly active facets for the oxidation of HMF and related reactions. [ABSTRACT FROM AUTHOR]

The polymerization of fused-ring acceptors (FRAs) to afford their corresponding polymeric acceptors for high-performance all-polymer solar cells (all-PSCs) has achieved remarkable progress in the past few years. However, due to the high degree of synthetic complexity for the monomer, the high-cost of these polymeric acceptors may limit their commercial applications. Thus, it is urgent to develop inexpensive and high-performance polymeric acceptors for all-PSCs. Herein, two novel polymeric acceptors (PBTzO and PBTzO-2F) have been designed and synthesized by copolymerization of noncovalently fused ring acceptors (NFRAs), which were employed in all-PSCs for the first time. Upon introducing the "noncovalently conformational locks (NoCLs)" in the backbone and selective fluorination of the end-group, photophysical and electrical properties, and solid-state packing properties of the NFRAs have been rationally tuned. As a result, the PBDB-T:PBTzO-2F based devices presented an excellent power conversion efficiency (PCE) of 11.04%, much higher than that of PBTzO based ones due to the increased charge generation and extraction, improved hole transfer and carrier mobilities, and reduced energy loss. More importantly, PBTzO-2F exhibited a much lower synthetic complexity (SC) index and higher figure-of-merit (FOM) values than the highperformance fused-ring acceptor based polymer acceptors (FRA-PAs) due to the simpler structures and more effective synthesis. This contribution provided a novel idea to achieve low-cost and high-performance all-PSCs. [ABSTRACT FROM AUTHOR]

Neither a single local feature nor a single global feature can completely characterize image information, and fusion of two or more complementary features can effectively improve retrieval performance in image retrieval. In this paper, a texture image retrieval method is proposed by fusing global and local features in the spatial domain and the transform domain. In the spatial domain, the local binary pattern (LBP) value of the image is calculated, and the histogram is established as the feature. In the transform domain, the dual-tree complex wavelet transform (DTCWT) is selected to decompose the image into sub-bands, in which the low-frequency approximate sub-band coefficients are modeled by Gaussian Mixture Model (GMM), magnitude sub-band coefficients are modeled by Gamma distribution model, and relative phase sub-band coefficients are modeled by von Mises distribution model; the LBP value of the magnitude sub-band coefficients and the improved local tetra pattern(ILTrP) value of the relative phase sub-band coefficients are calculated. According to the influence of different types of features on retrieval performance, the optimized weight coefficient is set for each type of feature, and accordingly a new similarity measurement formula is proposed. The experimental results on three different image databases of Brodatz database (DB1), MIT VisTex database (DB2) and STex (DB3) show that the average retrieval rate (ARR) of our method for databases DB1, DB2, and DB3 reaches 84.32%, 90.43% and 64.73%, respectively; and compared with the state-of-the-art methods, the ARR in DB1 increases by 1.04%, in DB2 by 0.35%, and in DB3 by 1.68%. [ABSTRACT FROM AUTHOR]

Separation efficiency of photogenerated carriers and CO 2 adsorption ability of the catalyst are two important factors affecting the photoreduction performance of CO 2. In view of the above analyses, leaf-vein like 2D-1D g-C 3 N 4 /P-MWNTs donor/acceptor semiconductor-carbon hybrid composite has been successfully prepared by the simple co-grinding/calcination processes. UV–vis DRS results showed that the modification of P-MWNTs can enhance the photo-absorption ability of the composite. Photoelectrochemical tests proved that 2D-1D Schottky-like barriers can enlarge the separation and transfer efficiency of photogenerated carriers. BET and CO 2 -adsorption tests exhibited that the introduction of P-MWNTs can greatly increase the CO 2 capture ability of the composite. CO 2 photoreduction experiments confirmed that the composite had much more excellent CO 2 photoreduction performance than the pure g-C 3 N 4 under the irradiation of UV–vis light or visible light. In-situ FTIR and 13C isotope tracer tests were applied to research the CO 2 photoreduction processes. Finally, the synergistic effect on CO 2 photoreduction process between electron transfer and CO 2 adsorption behavior has been discussed in total. [Display omitted] [ABSTRACT FROM AUTHOR]

The rapid advance of fused‐ring electron acceptors (FREAs) has greatly promoted the leap‐forward development of organic solar cells (OSCs). However, the synthetic complexity of FREAs may be detrimental for future commercial applications. Recently, nonfused‐ring electron acceptors (NREAs) have been developed to be a promising candidate to maintain a rational balance between cost and performance, of which the cores are composed of simple fused rings (NREAs‐I) or nonfused rings (NREAs‐II). Moreover, "noncovalently conformational locks", are used as an effective strategy to enhance the rigidity and planarity of NREAs and improve device performance. Herein, a novel series of NREAs‐II (PhO4T‐1, PhO4T‐2, and PhO4T‐3) is constructed as a valuable platform for exploring the impact of the end group engineering on optoelectronic properties, intermolecular packing behaviors, and device performance. As a result, a high power conversion efficiency of 13.76% is achieved for PhO4T‐3 based OSCs, which is much higher than those of the PhO4T‐1 and PhO4T‐2‐based devices. Compared with several representative FREAs, PhO4T‐3 possesses the highest figure‐of‐merit value of 133.45 based on a cost‐efficiency evaluation. This work demonstrates that the simple‐structured NREAs‐II are promising candidates for low‐cost and high‐performance OSCs. [ABSTRACT FROM AUTHOR]

Wide-light absorption performance and efficient carrier separation ability are the necessary conditions for excellent photocatalytic materials. In this research, g-C 3 N 4 QDs (CN QDs) and Au nano-particles (NPs) co-modified CeO 2 /Fe 3 O 4 micro-flowers (MFs) photocatalyst (CACeF) has been prepared. CO 2 photoreduction experiments showed that the composite had obviously enhanced photoreduction activity and photocatalytic stability. The yields of CO and CH 4 over it as catalyst in 4 h is about 5 and 8 times greater than that of pure CeO 2. Photoelectrochemical tests showed that the heterojunction between CN QDs and Au NPs can greatly improve the carrier separation ability and the light-utilization efficiency of photocatalysts. Besides, the excellent electronic transmission performance of Au NPs provided a specific channel for the electron transmission, and the strong local surface plasmon resonance (LSPR) of Au NPs resulted in a lot of hot-electrons can directly take part in the CO 2 photoreduction. The synergistic effect between CN QDs and Au NPs can further enhance the photocatalytic activity of the photocatalyst. Fe 3 O 4 QDs can ensure the effective recovery and reuse of the composite without affecting the photocatalytic performance of composite. Finally, a potential photoreduction mechanism of CN QDs and Au NPs co-modified CeO 2 /Fe 3 O 4 MFs photocatalyst were discussed in total. [Display omitted] • g-C3N4 QDs/Au NPs/CeO2/Fe3O4 has been prepared for the CO2 photoreduction. • Light-absorption performance of photocatalyst has been greatly enhanced. • Au efficiently speeds up the electrons' generation efficiency in semiconductors. • Synergistic effect of CN QDs/Au NPs enhanced the photoreduction performance. • Fe3O4 QDs can ensure the recovery without affecting the photocatalytic performance. [ABSTRACT FROM AUTHOR]

A novel halloysite (Hal) based acidic catalyst was synthesized by anchoring functional alkyl group and Cr site and catalyzed the selective conversion of mannose to 5-hydroxymethylfurfural (HMF) in NaCl-H 2 O/dimethyl sulfoxide/methyl isobutyl ketone (MIBK) biphasic system. Herein, adjusting the hydrophilicity/hydrophobicity of catalyst by modifying the octyl group can facilitate the HMF yield. The density functional theory (DFT) calculation and in-situ FT-IR results revealed that increasing the hydrophobicity of catalyst surface weakened the interaction between HMF, water molecule and acid sites and inhibited the rehydration of HMF. Moreover, the synergistic effect between Cr and sulfonic group active sites remarkedly promoted the isomerization of mannose to fructose and the dehydration of fructose to HMF, and the 48.1% yield of HMF was obtained. This study provides references for the high value conversion of hemicellulose with the high efficiency reaction system. [Display omitted] • Hal as support to prepared Lewis-Brönsted acid catalyst. • Regulating wettability of catalyst can effectively inhibit rehydration of HMF. • 48.1% of HMF yield was afforded in biphasic system. [ABSTRACT FROM AUTHOR]