Treatment of anastomotic stricture after rectal cancer operation by magnetic compression technique: A case report.

BACKGROUND: The treatment of postoperative anastomotic stenosis (AS) after resection of colorectal cancer is challenging. Endoscopic balloon dilation is used to treat stenosis in such cases, but some patients do not show improvement even after multiple balloon dilations. Magnetic compression technique (MCT) has been used for gastrointestinal anastomosis, but its use for the treatment of postoperative AS after colorectal cancer surgery has rarely been reported. CASE SUMMARY: We report a 72-year-old man who underwent radical resection of colorectal cancer and ileostomy one year ago. An ileostomy closure was prepared six months ago, but colonoscopy revealed a narrowing of the rectal anastomosis. Endoscopic balloon dilation was performed three times, but colonoscopy showed no significant improvement in stenosis. The AS was successfully treated using MCT. CONCLUSION: MCT is a minimally invasive method that can be used for the treatment of postoperative AS after colorectal cancer surgery.

Porous and Partially Dehydrogenated Fe2+ -Containing Iron Oxyhydroxide Nanosheets for Efficient Electrochemical Nitrogen Reduction Reaction (ENRR).

The design and development of efficient catalysts for electrochemical nitrogen reduction reaction (ENRR) under ambient conditions are critical for the alternative ammonia (NH3 ) synthesis from N2 and H2 O, wherein iron-based electrocatalysts exhibit outstanding NH3 formation rate and Faradaic efficiency (FE). Here, the synthesis of porous and positively charged iron oxyhydroxide nanosheets by using layered ferrous hydroxide as a starting precursor, which undergoes topochemical oxidation, partial dehydrogenated reaction, and final delamination, is reported. As the electrocatalyst of ENRR, the obtained nanosheets with a monolayer thickness and 10-nm mesopores display exceptional NH3 yield rate (28.5 µg h-1 mgcat. -1 ) and FE (13.2%) at a potential of -0.4 V versus RHE in a phosphate buffered saline (PBS) electrolyte. The values are much higher than those of the undelaminated bulk iron oxyhydroxide. The larger specific surface area and positive charge of the nanosheets are beneficial for providing more exposed reactive sites as well as retarding hydrogen evolution reaction. This study highlights the rational control on the electronic structure and morphology of porous iron oxyhydroxide nanosheets, expanding the scope of developing non-precious iron-based highly efficient ENRR electrocatalysts.

Noble-Metal-Metalloid Alloy Architectures: Mesoporous Amorphous Iridium-Tellurium Alloy for Electrochemical N2 Reduction.

Amorphous noble metals with high surface areas have attracted significant interest as heterogeneous catalysts due to the numerous dangling bonds and abundant unsaturated surface atoms created by the amorphous phase. However, synthesizing amorphous noble metals with high surface areas remains a significant challenge due to strong isotropic metallic bonds. This paper describes the first example of a mesoporous amorphous noble metal alloy [iridium-tellurium (IrTe)] obtained using a micelle-directed synthesis method. The resulting mesoporous amorphous IrTe electrocatalyst exhibits excellent performance in the electrochemical N2 reduction reaction. The ammonia yield rate is 34.6 µg mg-1 h-1 with a Faradaic efficiency of 11.2% at -0.15 V versus reversible hydrogen electrode in 0.1 M HCl solution, outperforming comparable crystalline and Ir metal counterparts. The interconnected porous scaffold and amorphous nature of the alloy create a complementary effect that simultaneously enhances N2 absorption and suppresses the hydrogen evolution reaction. According to theoretical simulations, incorporating Te in the IrTe alloy effectively strengthens the adsorption of N2 and lowers the Gibbs free energy for the rate-limiting step of the electrocatalytic N2 reduction reaction. Mesoporous chemistry enables a new route to achieve high-performance amorphous metalloid alloys with properties that facilitate the selective electrocatalytic reduction of N2.

Constructing Fast Transmembrane Pathways in a Layered Double Hydroxide Nanosheets/Nanoparticles Composite Film for an Inorganic Anion-Exchange Membrane.

Anion-exchange membranes (AEMs) with high conductivity are crucial for realizing next-generation energy storage and conversion systems in an alkaline environment, promising a huge advantage in cost reduction without using precious platinum group metal catalysts. Layered double hydroxide (LDH) nanosheets, exhibiting a remarkably high hydroxide ion (OH-) conductivity approaching 10-1 S cm-1 along the in-plane direction, may be regarded as an ideal candidate material for the fabrication of inorganic solid AEMs. However, two-dimensional anisotropy results in a substantially low conductivity of 10-6 S cm-1 along the cross-plane direction, which poses a hurdle to achieve fast ion conduction across the membrane comprising restacked nanosheets. In the present work, a composite membrane was prepared based on mixing/assembling micron-sized LDH nanosheets with nanosized LDH platelets (nanoparticles) via a facile vacuum filtration process. The hybridization with nanoparticles could alter the orientation of LDH nanosheets and reduce the restacking order, forming diversified fast ion-conducting pathways and networks in the composite membrane. As a result, the transmembrane conductivity significantly improved up to 1000-fold higher than that composed of restacked nanosheets only, achieving a high conductivity of 10-2 to 10-1 S cm-1 in both in-plane and cross-plane directions.

The Core/Shell Structure P Doped MoS2 @Ni3 S2 Nanorods Array for High Current Density Hydrogen Evolution in Alkaline and Acidic Electrolyte.

Electrocatalysis is the most promising strategy to generate clean energy H2 , and the development of catalysts with excellent hydrogen evolution reaction (HER) performance at high current density that can resist strong alkaline and acidic electrolyte environment is of great significance for practical industrial application. Therefore, a P doped MoS2 @Ni3 S2 nanorods array (named P-NiMoS) was successfully synthesized through successive sulfuration and phosphorization. P-NiMoS presents a core/shell structure with a heterojunction between MoS2 (shell) and Ni3 S2 (core). Furthermore, the doping of P modulates the electronic structure of the P-NiMoS; the electrons transfer from the t2g orbital of Ni element to the eg empty orbital of Mo element through the Ni-S-Mo bond at the Ni3 S2 and MoS2 heterojunction, facilitating the hydrogen evolution reaction. As a result, P-NiMoS exhibits excellent HER activity; the overpotential is 290 mV at high current density of 250 mA cm-2 in alkaline electrolyte, which is close to Pt/C (282 mV@250 mA cm-2 ), and P-NiMoS can stably evolve hydrogen for 48 h.

Aprotic Lithium-Carbon Dioxide Batteries: Reaction Mechanism and Catalyst Design.

In recent years, the combustion of fossil fuels leads to the release of a large amount of CO2 gas, which induces the greenhouse effect and the energy crisis. To solve these problems, researchers have turned their focus to a novel Li-CO2 battery (LCB). LCB has received much attention because of its high theoretical energy density and reversible CO2 reduction/evolution process. So far, the emerging LCB still faces many challenges derived from the slow reaction kinetics of discharge products. In this review, the latest status and progress of LCB, especially the influence of the structure design of cathode catalysts on the battery performance, are systematically elaborated. This review summarizes in detail the existing issues and possible solutions of LCB, which is of high research value for further promoting the development of Li-Air battery.

Atomically dispersed Fe-Nx species within a porous carbon framework: an efficient catalyst for Li-CO2 batteries.

Li-CO2 batteries are a promising energy storage system, while their practical application is still restricted by a lack of high-performance electrocatalysts for CO2 reduction and evolution reaction. Herein, we propose a metal-organic-framework-derived Fe-N-C electrocatalyst for Li-CO2 batteries. Within the Fe-N-C electrocatalyst, abundant Fe-Nx active sites at the molecular level were formed in the porous carbon framework, profiting from a host-guest chemistry strategy between Fe-mIm nanoclusters and metal organic framework precursors in the pyrolysis process. The confinement effect of the metal organic framework host was beneficial to limit the Fe-mIm nanoclusters at the molecular level, thus resulting in the formation of Fe-Nx sites with the high catalytic activity. Moreover, the as-prepared Fe-N-C catalyst is composed of dodecahedral nanoparticles stacking to form a unique three-dimensional structure with a large specific surface area and sufficient space, which not only favored the electron transport and CO2/Li+ diffusion but also promoted the deposition of discharge product Li2CO3 to ensure a high capacity. Therefore, the Fe-N-C based Li-CO2 battery exhibits high specific capacity (13 238 mA h g-1), good rate capability and excellent cyclability (140 cycles). Therefore, these encouraging results suggest an effective approach to obtain high-performance Fe-N-C electrocatalysts for Li-CO2 batteries.

Promoting charge separation by rational integration of a covalent organic framework on a BiVO4 photoanode.

For the first time, covalent organic frameworks (COF-TpPa and COF-TpPaC) are selected to combine with the BiVO4 photoanode through a covalent bond. The heterojunction and covalent connection of COFs and BiVO4 can promote the separation of carriers, and the -CH3 on the benzene ring in COF-TpPaC as an electron donor group can increase the carrier concentration of the photoanode. As a result, the TpPaC/BiVO4 photoanode shows the best performance. This covalent hybridization strategy opens a new insight into the development of COF-modified photoanodes.

Solar-enhanced hybrid lithium-oxygen batteries with a low voltage and superior long-life stability.

Lithium-oxygen batteries (LOBs) can suffer from large charge overpotentials during the sluggish oxygen evolution reaction (OER). Here, a strategy used in the photo-electrochemical (PEC) water oxidation area is integrated into hybrid LOBs. Coating α-Fe2O3 with NiOOH results in enhanced electrochemical properties, and the as-assembled hybrid LOBs deliver a low charge voltage of 3.03 V, high energy efficiency of 88%, and long-term stability for over 350 hours.

Efficient separation of photoexcited carriers in a g-C3N4-decorated WO3 nanowire array heterojunction as the cathode of a rechargeable Li-O2 battery.

Utilization of solar energy is very important for alleviating the global energy crisis; however, solar-to-electric energy conversion in a compact battery is a great challenge. High charging overpotential of conventional aprotic Li-O2 batteries still restricts their practical application. Herein, we propose a photo-involved rechargeable Li-O2 battery to not only realize direct solar-to-electric energy conversion/storage but also address the overpotential issue. In this photo-involved battery system, the g-C3N4-decorated WO3 nanowire array (WO3@g-C3N4 NWA) heterojunction semiconductor is used as both the photoelectrode and oxygen electrode. Upon charging under visible-light irradiation, the photoexcited holes and electrons are in situ generated on the WO3@g-C3N4 NWA heterojunction cathode. The fabrication of the heterojunction can distinctly reduce the recombination rate between electrons and holes, while photon-generated carriers are effectively and quickly separated and then migrate under a large current density. The discharge product (Li2O2) can be oxidized to O2 and Li+ with a reduced charging voltage (3.69 V) by the abundant photoexcited holes, leading to high energy efficiency, good cycling stability and excellent rate capability. This newly photo-involved reaction scheme could open new avenues toward the design of advanced solar-to-electric energy conversion and storage systems.

2D Layered Double Hydroxide Nanosheets and Their Derivatives Toward Efficient Oxygen Evolution Reaction.

Layered double hydroxides (LDHs) have attracted tremendous research interest in widely spreading applications. Most notably, transition-metal-bearing LDHs are expected to serve as highly active electrocatalysts for oxygen evolution reaction (OER) due to their layered structure combined with versatile compositions. Furthermore, reducing the thickness of platelet LDH crystals to nanometer or even molecular scale via cleavage or delamination provides an important clue to enhance the activity. In this review, recent progresses on rational design of LDH nanosheets are reviewed, including direct synthesis via traditional coprecipitation, homogeneous precipitation, and newly developed topochemical oxidation as well as chemical exfoliation of parent LDH crystals. In addition, diverse strategies are introduced to modulate their electrochemical activity by tuning the composition of host metal cations and intercalated counter-anions, and incorporating dopants, cavities, and single atoms. In particular, hybridizing LDHs with conductive components or in situ growing them on conductive substrates to produce freestanding electrodes can further enhance their intrinsic catalytic activity. A brief discussion on future research directions and prospects is also summarized.

All solid-state lithium-oxygen batteries with MOF-derived nickel cobaltate nanoflake arrays as high-performance oxygen cathodes.

Solid-state Li1+xAlxGe2-x(PO4)3 electrolytes with high ionic conductivity were prepared and successfully applied in lithium-oxygen batteries (LOBs). Combined with MOF-derived NiCo2O4 cathodes, the solid-state LOBs deliver a high discharge capacity and good rate performance. Moreover, enabled by such a bifunctional cathode, the as-assembled solid-state LOBs show enhanced reversibility and long-term cycling stability over 90 cycles.

All-metallic nanorattles consisting of a Pt core and a mesoporous PtPd shell for enhanced electrocatalysis.

The fabrication of nanorattles with controllable compositions and structures is very important for catalytic applications. Herein, we propose a facile method for synthesis of very unique all-metallic nanorattle consisting of a Pt core and a mesoporous PtPd shell (named Pt@mPtPd). Owing to its spatially and locally separated active inner Pt core and mesoporous PtPd shell, the Pt@mPtPd nanorattle shows the enhanced performance for oxygen reduction reaction. The newly designed Pt@mPtPd nanorattle is quite different from traditional nanorattles with porous carbon and silica shell in its catalytically functional mesoporous metallic shell. The proposed facile method is highly valuable for the design of all-metallic nanorattle with controllable compositions and desired functions.

Hollow Mesoporous Fe2O3 Nanospindles/CNTs Composite: An Efficient Catalyst for High-Performance Li-O2 Batteries.

The design of mesoporous or hollow transition metal oxide/carbon hybrid catalysts is very important for rechargeable Li-O2 batteries. Here, spindle-like Fe2O3 with hollow mesoporous structure on CNTs backbones (Fe2O3-HMNS@CNT) are prepared by a facile hydrolysis process combined with low temperature calcination. Within this hybrid structure, the hollow interior and mesoporous shell of the Fe2O3 nanospindles provide high specific surface area and abundant catalytical active sites, which is also beneficial to facilitating the electrolyte infiltration and oxygen diffusion. Furthermore, the crisscrossed CNTs form a three-dimensional (3D) conductive network to accelerate and stabilize the electron transport, which leads to the decreasing internal resistance of electrode. As a cathodic catalyst for Li-O2 batteries, the Fe2O3-HMNS@CNT composite exhibits high specific capacity and excellent cycling stability (more than 100 cycles).

Direct fabrication of bi-metallic PdRu nanorod assemblies for electrochemical ammonia synthesis.

Electrochemical reduction of N2 represents a very attractive approach for sustainable NH3 production at environmental temperature and pressure. The design of highly branched Pd-based nanoarchitectonics is very important for the electrocatalytic N2 reduction reaction (NRR). Herein, we propose a very simple synthetic method for direct fabrication of unique bi-metallic PdRu nanorod assemblies (PdRu NRAs) with high yield in an aqueous solution. Owing to their branched shape together with bi-metallic compositions, the self-supported PdRu NRAs assembled with staggered nanorods show high catalytic activity and superior durability for the NRR. The presented direct synthetic strategy is very valuable for the design of active branched metallic catalysts for the NRR.

Ultralong Ternary PtRuTe Mesoporous Nanotubes Fabricated by Micelle Assembly with a Self-Sacrificial Template.

High surface area and fast mass transport rate are important to enhance the activity and stability of catalysts. In this work, tellurium nanowires and F127 triblock copolymer are used as self-sacrificial and soft templates, respectively, to synthesize PtRuTe mesoporous nanotubes (MNTs). The designed PtRuTe MNTs show uniformly distributed mesopores and an internally hollow structure, which can effectively improve Pt utilization, the catalytic activity and durability, and CO tolerance for the methanol oxidation reaction. Very different from previous 1D metallic catalysts with solid interiors and smooth surfaces, PtRuTe MNTs are unique, with a mesoporous exterior and hollow interior. The facile route presented herein is very feasible for fabricating 1D mesoporous metallic catalysts.

Electrochemical Fabrication of Porous Au Film on Ni Foam for Nitrogen Reduction to Ammonia.

Electrochemical reduction of N2 to NH3 provides an alternative strategy to replace the industrial Haber-Bosch process for facile and sustainable production of NH3 . The development of efficient electrocatalysts for the nitrogen reduction reaction (NRR) is highly desired. Herein, a micelle-assisted electrodeposition method is presented for the direct fabrication of porous Au film on Ni foam (pAu/NF). Benefiting from its interconnected porous architectonics, the pAu/NF exhibits superior NRR performance with a high NH3 yield rate of 9.42 µg h-1 cm-2 and a superior Faradaic efficiency of 13.36% at -0.2 V versus reversible hydrogen electrode under the neutral electrolyte (0.1 m Na2 SO4 ). The proposed micelle-assisted electrodeposition strategy is highly valuable for future design of active NRR catalysts with desired compositions toward various electrocatalysis fields.

Trimetallic PtPdNi-Truncated Octahedral Nanocages with a Well-Defined Mesoporous Surface for Enhanced Oxygen Reduction Electrocatalysis.

Engineering the architectures and compositions of noble metal-based nanocrystals is an effective strategy to optimize their catalytic performance. Herein, we report the synthesis of unique trimetallic PtPdNi mesoporous-truncated octahedral nanocages (PtPdNi MTONs), which is simply performed by first constructing Pd@PtPdNi core-shell mesoporous truncated octahedra (Pd@PtPdNi MTOs) and further selective etching of the Pd cores using concentrated nitric acid. The rational combinations of polyhedral shape, mesoporous surface, and hollow structure provide sufficiently exposed active sites and efficient reactant permeability. With these unique properties, the PtPdNi MTONs show improved catalytic activity and stability toward the oxygen reduction reaction.