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Replacing the slow protonation process of oxygen evolution reaction (OER) with the fast protonation of alcohol electro‐oxidation can decrease the driving potentials, thus improving overall efficiency of electrochemical devices. However, the formation of effective catalytic sites for alcohol oxidation remains challenging in accelerating protonation to inhibit metal leaching and improve catalyst stability. Herein, asymmetric Ni‐O‐Cr sites are constructed by alloying Cr into the NiO matrix to optimize coordination environments, showing significantly enhanced stability during alcohol electro‐oxidation. The asymmetric Ni‐O‐Cr can maintain constant valence states of Cr and Ni during alcohol oxidation, efficiently suppressing metal dissolution even at high oxidation potentials. In situ electrochemical characterizations combined with theoretical calculations indicate that asymmetric Ni‐O‐Cr can improve adsorption and activation of OH* and alcohol molecules compared to pure NiO, thus increasing anodic kinetics. The theoretical results also indicate that the smaller gap of Ni 3d‐O 2p in asymmetric Ni‐O‐Cr strengthens charge transfer, leading to fast protonation of catalytic sites with enhanced stability. This work gives insights into boosting anodic protonation using asymmetric sites‐enriched solid‐solution electrocatalysts. [ABSTRACT FROM AUTHOR]

In order to solve the problem that small defects hidden behind pipeline support parts are difficult to detect effectively in small spaces, such as offshore oil platforms, a meander-coil-type dual magnetic group circumferential magnetostrictive guided wave transducer is developed in this paper. The transducer, which consists of a coil, two sets of permanent magnets, and a magnetostrictive patch, can excite a high-frequency circumferential shear horizontal (CSH) guided wave. The energy conversion efficiency of the MPT is optimized through magnetic field simulation and experiment, and the amplitude of the defect signal is enhanced 1.9 times. The experimental results show that the MPT developed in this paper can effectively excite and receive CSH2 mode guided waves with a center frequency of 1.6 MHz. Compared with the traditional PPM EMAT transducer, the excitation energy of the transducer is significantly enhanced, and the defects of the 2 mm round hole at the back of the support can be effectively detected. [ABSTRACT FROM AUTHOR]

The exploration of new heterojunction materials is of great significance in reducing the cost of existing noble metal catalysts and thus realizing the large-scale application of electrocatalytic hydrolysis technology. Herein, a novel CoP/CoMoP2 heterojunction was synthesized and served as a hydrogen evolution reaction (HER) electrocatalyst. The heterojunction has morphology of nanoporous structure, which is conducive to exposing more active sites and facilitating bubbles transport. The charge distribution is optimized by a strong interface interaction between CoP and CoMoP2. The catalyst's conductivity and the adsorption properties of the intermediates have both been enhanced. CoP/CoMoP2 demonstrates excellent HER activity with an overpotential of 93.6 mV at 10 mA·cm−2, which is competitive with the reported performance of analogous electrocatalysts. This work provides insights into the development of innovative phosphide-based heterojunction electrocatalysts. [ABSTRACT FROM AUTHOR]

The fabrication of heterointerface materials with hierarchical morphologies more than two levels is a challenging yet promising approach to achieve optimal electrocatalyst for hydrogen evolution reaction (HER). Here, using a facile two-step method, we are able to prepare the Ni2P/(Co,Ni)OOH heterointerface with a three-level hierarchy morphology. The multiple levels of hierarchy structures not only offer considerable area for active sites loading, but also facilitate the substance transportation, both beneficial for HER. Meanwhile, the strong charge transfer at the Ni2P/(Co,Ni)OOH heterointerface eliminates the spin asymmetry and achieves the thermos-neutral adsorption of active H species. Moreover, the resulted Coulomb attraction stacks the two materials firmly, facilitating the stability. Density functional theory (DFT) and in-situ Raman measurements reveal the sufficient Ni atoms acting as the active sites. With these merits, the Ni2P/(Co,Ni)OOH exhibits much better HER activity than the separate Ni2P or (Co,Ni)OOH, affording a current density of 100 mA/cm2 at an overpotential of 169 mV and a Tafel slope of 41 mV/dec, when tested in alkaline electrolyte. This work provides inspiration for optimizing the intrinsic HER activity utilizing multiple-level hierarchy structures. [ABSTRACT FROM AUTHOR]

The electrocatalytic hydrogen evolution activity of transition metal sulfide heterojunctions are significantly increased when compared with that of a single component, but the mechanism behind the performance enhancement and the preparation of catalysts with specific morphologies still need to be explored. Here, we prepared a Co9S8/MoS2 heterojunction with microsphere morphology consisting of thin nanosheets using a facile two-step method. There is electron transfer between the Co9S8 and MoS2 of the heterojunction, thus realizing the redistribution of charge. After the formation of the heterojunction, the density of states near the Fermi surface increases, the d-band center of the transition metal moves downward, and the adsorption of both water molecules and hydrogen by the catalyst are optimized. As a result, the overpotential of Co9S8/MoS2 is superior to that of most relevant electrocatalysts reported in the literature. This work provides insight into the synergistic mechanisms of heterojunctions and their morphological regulation. [ABSTRACT FROM AUTHOR]

The coordination environment is crucial for the activity of an electrocatalyst, which defines the interaction between the central and adjacent atoms. In traditional 2D MX2 (M = Mo, W, etc., X = S, Se), M is usually coordinated with 6 X atoms in either trigonal prismatic (2H) or octahedral (1T) polyhedrons. With such a coordination configuration, only the edge X sites exhibit activity for hydrogen evolution reaction (HER). Here, a planar‐coordination transition metal chalcogenide, PdSe2 is reported, as an efficient electrocatalyst for the HER in an alkaline electrolyte. By reducing the spatial polyhedron coordination to planar polygon coordination, the M sites in PdSe2 can be efficiently activated to interact with the adsorptive intermediates. As a result, both Pd and Se atoms act as active sites for hydrogen evolution with neutral adsorption ability. With an overpotential of 138 mV at 10 mA cm−2, this work advances the exploration of planar‐coordination HER electrocatalysts. [ABSTRACT FROM AUTHOR]

Significant efforts have been dedicated to boosting the electrocatalytic activity of Co9S8 for the oxygen evolution reaction (OER); however, with limited improvement in its intrinsic activity, which relies on careful band engineering. Fe possesses one less 3d electron and lower electronegativity than Co, suggesting a higher d‐band center when forming polyhedron with S anions. Here, to improve the intrinsic activity by elevating the d‐band center, the six‐coordinated octahedrons in Co9S8 are redesigned utilizing an Fe‐incorporated topochemical deintercalation method. Through substituting partial Co octahedrons by Fe octahedrons with higher d‐band, the overall d‐band center is regulated to achieve optimized adsorption and thus superior OER activity. With a reduction of 95 mV on the overpotential (at 10 mA cm−2), this work sheds lights on the design of OER catalysts through polyhedron engineering using topochemical deintercalation. [ABSTRACT FROM AUTHOR]

Low excitation voltage for an electromagnetic acoustic transducer (EMAT) is necessary for the petrochemical equipment and facilities inspection, which work at high-temperatures, to avoid potential explosion. However, low excitation voltage causes low signal-to-noise ratio (SNR) signals that are difficult to extract features, especially in a high-temperature environment, which causes high noise. In this study, a denoising method called the variational wavelet ensemble empirical (VWEE) method was proposed by combining the advantages of the variational modal decomposition (VMD), wavelet threshold (WT) denoising, and ensemble empirical mode decomposition (EEMD) methods. To validate the VWEE method, EMAT signals obtained in the temperature range of 25 to 700 °C were analyzed. The results show that, compared with VMD, WT and empirical mode decomposition denoising methods, the SNR of proposed method is improved more than two times. The VWEE method dramatically improved the SNR of a high-temperature EMAT signal and enhanced the accuracy of defect echos extraction. [ABSTRACT FROM AUTHOR]

Modulating the electronic states of electrocatalysts is critical for achieving efficient hydrogen evolution reaction (HER). However, how to develop electrocatalysts with superior electronic states is an urgent challenge that must be addressed. Herein, we prepared the CoP/MoS 2 heterojunction with a microsphere morphology consisting of thin nanosheets using a facile two-step method. The catalyst's ultrathin nanosheet structure not only provides an extensive surface area for exposing active sites, but it also enables ion transport and bubble release. Electron transfer occurs between CoP and MoS 2 , optimizing the heterojunction's charge distribution and enhancing the intermediates' adsorption capabilities. As a result, the CoP/MoS 2 heterojunction exhibits outstanding electrocatalytic hydrogen evolution activity with an overpotential of only 88 mV at a current density of 10 mA cm -2 , which exceeds both the sulfide heterojunction Co 9 S 8 /MoS 2 and the phosphide heterojunction CoP/CoMoP 2 . The experimental results and DFT calculation results show that the former has stronger synergistic effects and higher HER activity. This work sheds light on the exploration of efficient heterojunction electrocatalysts with excellent electronic structures., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

The elucidation of resources pertaining to the Chimonanthus praecox varieties and the establishment of a fingerprint serve as crucial underpinnings for advancing scientific inquiry and industrial progress in relation to C . praecox . Employing the SSR molecular marker technology, an exploration of the genetic diversity of 175 C . praecox varieties (lines) in the Yanling region was conducted, and an analysis of the genetic diversity among these varieties was carried out using the UPDM clustering method in NTSYSpc 2.1 software. We analyzed the genetic structure of 175 germplasm using Structure v2.3.3 software based on a Bayesian model. General linear model (GLM) association was utilized to analyze traits and markers. The genetic diversity analysis revealed a mean number of alleles (Na) of 6.857, a mean expected heterozygosity (He) of 0.496 3, a mean observed heterozygosity (Ho) of 0.503 7, a mean genetic diversity index of Nei՚s of 0.494 9, and a mean Shannon information index of 0.995 8. These results suggest that the C . praecox population in Yanling exhibits a rich genetic diversity. Additionally, the population structure and the UPDM clustering were examined. In the GLM model, a total of fifteen marker loci exhibited significant ( P < 0.05) association with eight phenotypic traits, with the explained phenotypic variation ranging from 14.90% to 36.03%. The construction of fingerprints for C . praecox varieties (lines) was accomplished by utilizing eleven primer pairs with the highest polymorphic information content, resulting in the analysis of 175 SSR markers. The present study offers a thorough examination of the genetic diversity and SSR molecular markers of C . praecox in Yanling, and establishes a fundamental germplasm repository of C . praecox , thereby furnishing theoretical underpinnings for the selection and cultivation of novel and superior C . praecox varieties, varietal identification, and resource preservation and exploitation.