Unique Porous Architecture Research Articles

Bijel-based mesophotoreactor with integrated carbon nitride for continuous-flow photocatalysis

The integration of continuous-flow technologies with heterogeneous photocatalysis has recently emerged as a promising strategy for the development of sustainable processes. Although conventional packed bed reactors have been extensively utilized in industrial catalytic applications, they face challenges related to energy transfer in the photocatalytic systems. This study presents an innovative approach to address this issue by integrating heterogeneous photocatalysts with an organic polymer, leading to the fabrication of a mesophotoreactor featuring a bijel-based structural configuration. This novel strategy involves hybridizing polypentadecalactone and in situ confining of carbon nitride in a bicontinuous porous mesoarchitecture. The structural and physicochemical properties of the resulting catalytic composite material are evaluated through an array of characterization methods, affirming the successful integration of carbon nitride within the overall structure. The unique bicontinuous porous architecture of the composite and its suitability for industrial applications is verified, as exemplified by its exceptional efficiency in the photodegradation of methylene blue (>99 %) under flow conditions and remarkable stability up to three reaction cycles. A mathematical model is developed to describe continuous photocatalytic processes occurring in the novel tubular mesophotoreactor, with a specific focus on the degradation of the methylene blue dye. This model is successfully validated, leading to results in agreement with the experimental measurements. Additionally, fluid dynamics simulations demonstrate that the mesophotoreactor design allows for the effective diffusion of light through its channels, resulting in higher irradiation levels compared to conventional systems such as packed bed reactors. The innovative design of the catalytic reactor presented in this work offers a versatile and efficient alternative to the conventional heterogeneous systems, significantly broadening the range of applications for photocatalytic processes.

Improving H2 gas sensing with ZnMn2O4/Polypyrrole Nanocomposite

Here we report the operation of p-p heterojunction for improving the H2 gas sensing performance of ZnMn2O4/Polypyrrole nanocomposite (PZ) at room temperature. ZnMn2O4 (ZM) with a unique cubic morphology and porous architecture was synthesized via a one-step hydrothermal method. Polypyrrole (PPy) fibers and PZs were prepared through chemical oxidative polymerization of pyrrole monomers in the absence and presence of different weight percentages (wt%) of ZM, respectively. Our findings show that the PZs consisted of microcubic ZMs with dimensions of approximately 8 μm, covered with wire-like PPy fibers. The partial protonated PPy and different wt% of microcubic ZM have a significant effect on H2 gas sensing. The response of our hand-made sensor increased with increasing wt% of ZM and gas level. The PZ samples exhibited the highest response of 1.23 (the lowest tres value of 21.6 s) at a concentration of 15000 (2500) ppm H2 gas. Furthermore, the PZ sample contains 10 wt% of ZM demonstrated excellent long-term stability in response after six months, which indicates the accuracy and reliability of the sensor. H2 gas mechanism of the PZ sensor was studied in details. The advantage of p-p heterojunction could provide a new perspective for H2 gas sensing applications.

Enhanced hydrotreating performance of hierarchical NiMo-S/Al2O3 catalysts through ZrO2 incorporation and template-driven structural modulation

A dual template-assisted approach for optimizing support structures to enhance catalytic efficiency in hydrotreating reactions is presented. Catalysts synthesized using activated carbon (AC) templates exhibited significantly higher activity in both hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) compared to those prepared with starch (ST) templates. The unique porous architecture, characterized by well-distributed meso- and macropores, facilitated efficient access of bulky molecules to the active sites. On the other hand, while the reactivity in the selective opening of the naphthenic ring (SONR), which is indicative of hydrocracking functionality, was similar across all catalysts, those modified with Zr exhibited a slight improvement. The catalysts displayed bifunctional characteristics, and their performance was influenced by the amphoteric nature of the support and the specific ratios of active species on the surface. A clear correlation between catalytic activity, selectivity, and the distribution of active sites was established.

Single step grown porous polycrystalline nickel microstructures with ultra-thin defect rich surface oxide for alkaline water oxidation

Investigation on the intrinsic catalytic activity of structurally diverse polycrystalline nickel microstructures such as porous nickel sheets (PNS), porous folded/curled nickel structures (PFNS) and porous nickel balls (PNB) revealed the surface bounded electrocatalytic activities within an alkaline reaction environment for water oxidation. Nickel microstructures were grown via template/surfactant-free, single step solution combustion technique in air atmosphere. The distinct morphologies (porous nickel sheets, porous folded/curled nickel structures and porous nickel balls) were achieved through changing the quantity of HNO3 in the reaction mixture. The physicochemical characterisations were done with XRD, FESEM, EDS and XPS. Microscopic studies revealed the growth of nickel grains with numerous macro pores forming microstructures in distinct morphologies. The O ls spectra of XPS studies revealed the presence of O−/O2− sites and Ni 2p spectra were distinguished between the formation of Ni0/Ni2+/Ni3+ states, implied the existence of surface oxide with plenty of defects. The synergistic effect results from the formation of microscopic porous architectures with defect rich surface oxide on the electrochemical behaviour and OER activity of PNS, PFNS and PNB were discussed with electrochemical techniques such as CV, LSV, EIS and CP. The OER kinetics in terms of relatively low value of overpotential at 10 mA cm−2 and Tafel slope along with high specific activity of PNS/GCE with respect to PFNS/GCE and PNB/GCE were attributed to the combined effect of increase in electrochemical surface area, high roughness factor and fast charge transfer kinetics. The better electrochemical performance and OER activities of porous nickel sheets in comparison with folded/curled nickel structures and nickel balls is contributed to the unique 2D porous architecture with plenty of oxygen vacancies. This structure not only expose more surface for the formation of passive oxide layer in an alkaline reaction environment but also exhibit facile charge transport properties, causes the generation of numerous surface-active sites for electrocatalytic water oxidation. The outcome of our work gives new insights on the surface electrochemistry of polycrystalline nickel, enables micro-structuring as a prospective strategy towards the optimization of electrocatalysts as anode material for alkaline water oxidation.

Controllable preparation of polymetallic selenides and their application in high-performance supercapacitors

Transition metal selenides (TMSes) have garnered considerable interest as potential electrode materials for supercapacitors owing to their promising electrochemical properties, but the fabrication of intricate nanostructured electrodes utilizing these compounds still poses a formidable challenge. In this study, a ternary transition metal selenide nanomaterial Cu2MnSnSe4, which has rarely been reported, was successfully synthesized on nickel foam (NF) by a simple solvothermal method, and its electrochemical properties have not been concern by researchers. We systematically studied the electrochemical properties of the materials synthesized under different solvothermal reaction times, and discussed the relationship between reaction time and electrochemical properties. The unique porous surface architecture of the sea urchin-like nanosphere configuration in Cu2MnSnSe4 material grants it a significantly enhanced specific surface area and a proliferation of electrochemically active sites, surpassing those of other comparable materials. According to the synthesis reaction time from short to long, the materials were named Cu2MnSnSe4-1 (20h), Cu2MnSnSe4-2 (25h) and Cu2MnSnSe4-3 (30h), among which Cu2MnSnSe4-2 showed better electrochemical performance than the other two. Electrochemical results show that the prepared Cu2MnSnSe4-2 electrode possesses an outstanding specific capacitance of 930.6 mF cm−2 at 2 mA cm−2, good rate performance (92 %), and a capacitance retention rate is 67.57 % after 3000 cycles of charging and discharging. The asymmetric supercapacitor (ASC) exhibits a voltage window spanning 0–1.6 V, reaching an outstanding energy density of 0.076 mWh cm−2 at 1.47 mW cm−2. Remarkably, it maintains 129.63 % cycling stability even after enduring 5000 charge-discharge cycles. From the above results, it can be seen that Cu2MnSnSe4 material may be a promising electrode material with broad application prospects in the practical application of supercapacitors.

3D Nickel–Manganese bimetallic electrocatalysts for an enhanced hydrogen evolution reaction performance in simulated seawater/alkaline natural seawater

In this paper, we report an inexpensive one-step synthesis of self-supported 3D nickel-manganese (NiMn) bimetallic coatings and their application for the hydrogen evolution reaction in simulated seawater (1 M KOH + 0.5 M NaCl) and alkaline natural seawater (1 M KOH + natural seawater). These binary coatings were electrodeposited on a titanium substrate using a facile electrochemical deposition method by a dynamic hydrogen bubble template technique. The as-deposited NiMn coatings with variable Mn amounts produce typical globular and unique porous architecture with abundant pores of different sizes. The activity of these fabricated catalysts towards the hydrogen evolution reaction was investigated by linear sweep voltammetry towards simulated seawater and alkaline natural seawater at different temperatures. The surface morphology and composition of the catalysts were also characterized by scanning electron microscopy and inductively coupled plasma optical emission spectroscopy. The as-prepared NiMn/Ti electrocatalyst, which was electrodeposited using a chemical bath containing Ni2+ and Mn2+ ions with a molar ratio of Ni2+:Mn2+ = 1:5, exhibits excellent hydrogen evolution activity in simulated seawater with an ultra-low overpotential of 64.2 mV to reach a current density of 10 mA cm−2. It is noteworthy that this NiMn/Ti electrocatalyst also achieves a current density of 10 mA cm−2 in alkaline natural seawater with a comparably low overpotential of 79.3 mV. The current densities increase by ca. 1.75–2.35 times with an increase in temperature from 25 °C to 75 °C for hydrogen evolution in both electrolytes. This bimetallic catalyst has shown excellent long-term stability at a constant potential of −0.23 V (vs. RHE) and a constant current density of 10 mA cm−2 for 10 h, which ensures higher durability and robustness for practical application of seawater splitting technology.

Iron Sulfide Microspheres Supported on Cellulose-Carbon Nanotube Conductive Flexible Film as an Electrode Material for Aqueous-Based Symmetric Supercapacitors with High Voltage.

Nanostructured iron disulfide (FeS2) was uniformly deposited on regenerated cellulose (RC) and oxidized carbon nanotube (CNT)-based composite films using a simple chemical bath deposition method to form RC/CNT/FeS2 composite films. The RC/CNT composite film served as an ideal substrate for the homogeneous deposition of FeS2 microspheres due to its unique porous architecture, large specific surface area, and high conductivity. Polypyrrole (PPy), a conductive polymer, was coated on the RC/CNT/FeS2 composite to improve its conductivity and cycling stability. Due to the synergistic effect of FeS2 with high redox activity and PPy with high stability and conductivity, the RC/CNT/FeS2/PPy composite electrode exhibited excellent electrochemical performance. The RC/CNT/0.3FeS2/PPy-60 composite electrode tested with Na2SO4 aqueous electrolyte could achieve an excellent areal capacitance of 6543.8 mF cm-2 at a current density of 1 mA cm-2. The electrode retained 91.1% of its original capacitance after 10,000 charge/discharge cycles. Scanning electron microscopy (SEM) images showed that the ion transfer channels with a pore diameter of 5-30 μm were formed in the RC/CNT/0.3FeS2/PPy-60 film after a 10,000 cycle test. A symmetrical supercapacitor device composed of two identical pieces of RC/CNT/0.3FeS2/PPy-60 composite electrodes provided a high areal capacitance of 1280 mF cm-2, a maximum energy density of 329 μWh cm-2, a maximum power density of 24.9 mW cm-2, and 86.2% of capacitance retention after 10,000 cycles at 40 mA cm-2 when tested at a wide voltage window of 1.4 V. These results demonstrate the greatest potential of RC/CNT/FeS2/PPy composite electrodes for the fabrication of high-performance symmetric supercapacitors with high operating voltages.

Two-dimensional architecture of N,S-codoped nanocarbon composites embedding few-layer MoS2 for efficient lithium storage.

The exploration and advancement of highly efficient anode materials for lithium-ion batteries (LIBs) are critical to meet the growing demands of the energy storage market. In this study, we present an easily scalable synthesis method for the one-pot formation of few-layer MoS2 nanosheets on a N,S dual-doped carbon monolith with a two-dimensional (2D) architecture, termed MoS2/NSCS. Systematic electrochemical measurements demonstrate that MoS2/NSCS, when employed as the anode material in LIBs, exhibits a high capacity of 681 mA h g-1 at 0.2 A g-1 even after 110 cycles. The exceptional electrochemical performance of MoS2/NSCS can be attributed to its unique porous 2D architecture. The few-layer MoS2 sheets with a large interlayer distance reduce ion diffusion pathways and enhance ion mobility rates. Additionally, the N,S-doped porous carbon matrix not only preserves structural integrity but also facilitates electronic conductivity. These combined factors contribute to the reversible electrochemical activities observed in MoS2/NSCS, highlighting its potential as a promising anode material for high-performance LIBs.

Tunable Pt-NiO interaction-induced efficient electrocatalytic water oxidation and methanol oxidation.

Metal-support interaction engineering is considered an efficient strategy for optimizing the catalytic activity. Nevertheless, the fine regulation of metal-support interactions as well as understanding the corresponding catalytic mechanisms (particularly those of non-carbon support-based counterparts) remains challenging. Herein, a controllable adsorption-impregnation strategy was proposed for the preparation of a porous nonlayered 2D NiO nanoflake support anchored with different forms of Pt nanoarchitectures, i.e. single atoms, clusters and nanoparticles. Benefiting from the unique porous architecture of NiO nanosheets, abundant active defect sites facilitated the immobilization of Pt single atoms onto the NiO crystal, resulting in NiO lattice distortion and thus changing the valence state of Pt, chemical bonding, and the coordination environment of the metal center. The synergy of the porous NiO support and the unexpected Pt single atom-NiO interactions effectively accelerated mass transfer and reduced the reaction kinetic barriers, contributing to a significantly enhanced mass activity of 5.59 A mgPt -1 at an overpotential of 0.274 V toward the electrocatalytic oxygen evolution reaction (OER) while 0.42 A mgPt -1 at a potential of 0.7 V vs. RHE for the methanol oxidation reaction (MOR) in an alkaline system, respectively. This work may offer fundamental guidance for developing metal-loaded/dispersed support nanomaterials toward electrocatalysis through the fine regulation of metal-support interactions.

Coordination polymer and layered double hydroxide dual-precursors derived polymetallic phosphides confined in N-doped hierarchical porous carbon nanoflower as a highly efficient bifunctional electrocatalyst for overall water splitting

Controllable construction of proficient electrocatalyst with 3D hierarchical architecture to achieve low cost and high efficient overall water splitting is of great significance to the sustainable development. Hereby, trimetallic phosphides confined in N-doped carbon nanoflowers (CoNiP/CoNiFeP@NCNFs) were fabricated using CoNi coordination polymer nanoflowers/CoNiFe layered double hydroxide (CoNi CPNFs/CoNiFe LDH) as precursors followed by phosphorization. Benefiting from the unique 3D hierarchical porous architecture, preeminent conductivity, high specific surface area, efficient mass/charge transfer and synergic effect of various transition metals, the well-designed CoNiP/CoNiFeP@NCNFs exhibit extraordinary electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. Particularly, this novel material can work as a bifunctional catalyst in an integrated water-splitting electrolyzer, which only requires a low voltage of 1.55 V to realize the current density of 10 mA cm−2 with admirable durability (at least 28 h). This work certified the foreground of composites assembled by 3D hierarchical porous carbon and polymetallic phosphides for overall water splitting. It also provided a novel proposal for the rational designing and constructing highly active electrocatalysts by using coordination polymer and LDH as dual-precursors.

Defect engineering of hollow porous N, S co-doped carbon spheres-derived materials for high-performance hybrid supercapacitors

Defect engineering, such as introducing heteroatoms and vacancies into the electrode materials, provides a feasible strategy for boosting the electrochemical characteristics of hybrid supercapacitors. In this work, hollow N, S co-doped carbon (HNSC) spheres with high specific surface area are fabricated through the carbonization-etching process. Thanks to the unique porous architecture and multiple heteroatoms doping, the obtained HNSC electrode achieves an excellent capacitance of 330.4 F g−1 at 1 A g−1 and superior capacitance retention of 97 % after 10,000 cycles in 6 M KOH. Subsequently, the Co3S4 nanoparticles with controllable sulfur vacancies (Vs-Co3S4) are homogeneously deposited on the HNSC skeleton by a facile chemical reduction strategy. The fabricated Vs-Co3S4/HNSC cathode exhibits a compelling electrochemical capacity of 497.2 C g−1 at 1 A g−1 and a prominent cycle life of 98.1 % after 10,000 cycles in 6 M KOH. Noticeably, benefiting from the defects regulation and unique structures of HNSC and Vs-Co3S4/HNSC, the constructed hybrid supercapacitor of VS-Co3S4/HNSC//HNSC reaches a marvelous energy density of 71.4 Wh kg−1 at 925.3 W kg−1 with only 8.1 % capacity loss within 15,000 cycles at 10 A g−1. Such eminent electrochemical features inspire the rational design of advanced defect-modulated electrode materials for energy storage applications.

Pyroptosis Induction with Nanosonosensitizer-Augmented Sonodynamic Therapy Combined with PD-L1 Blockade Boosts Efficacy against Liver Cancer.

Induction of pyroptosis can promote anti-PD-L1 therapeutic efficacy due to the release of pro-inflammatory cytokines, but current approaches can cause off target toxicity. Herein, a phthalocyanine-conjugated mesoporous silicate nanoparticle (PMSN) is designed for amplifying sonodynamic therapy (SDT) to augment oxidative stress and induce robust pyroptosis in tumors. The sub-10nm diameter structure and c(RGDyC)-PEGylated modification enhance tumor targeting and renal clearance. The unique porous architecture of PMSN doubles ROS yield and enhances pyroptotic cell populations in tumors (25.0%) via a cavitation effect. PMSN-mediated SDT treatment efficiently reduces tumor mass and suppressed residual tumors in treated and distant sites by synergizing with PD-L1 blockade (85.93% and 77.09%, respectively). Furthermore, loading the chemotherapeutic, doxorubicin, into PMSN intensifies SDT-pyroptotic effects and increased efficacy. This is the first report of the use of SDT regimens to induce pyroptosis in liver cancer. This noninvasive and effective strategy has potential for clinical translation.

Optimizing D-band center of tube brush-like CoZn13/Co/ZnO architecture with multiple-heterointerfaces enhancing ion/electron migration toward pseudocapacitive storage

The exploration of hierarchical heterostructures with heterointerfaces have proven indispensable for enhancing ion/electron migration of efficient energy storage. Herein, a fascinating design of CoZn13/Co/ZnO hierarchically porous nanostructures (CZCZ HPNs) with rich heterointerfaces concurrently encapsulated into N-doped carbon (NC), growing on three-dimensional Ni foam wrapped by N-doped graphene (denoted as CZCZ/NC HPNs) is showcased for pseudocapacitive storage. The ingeniously construction of CZCZ HPNs/NC features powerful built-in electric field (BIEF) introduced by well-defined heterointerface for boosting electronic/ionic transport dynamics, and unique porous hierarchical architectures for reinforcing the structural and electrochemical stability. Notably, combined with the differential charge density analysis, the BIEF in CZCZ/NC HPNs generated by two heterointerfaces of Co-ZnO and CoZn13-ZnO can offer additional driving forces for promoting electron transfer. The d band centers of different heterojunctions remarkably shift negatively in comparison with those of the monomers, indicative of lower electron/ion transfer energy barrier. Additionally, the CZCZ/NC HPNs as a positive electrode and porous γ-Fe2O3 nanorods wrapped by NC (γ-Fe2O3/NC) as a negative electrode are employed to assemble a soft-packed hybrid supercapacitor device with ultrahigh energy density of ∼107.2 Wh kg−1 at ∼399.9 W kg−1. This work highlights an in-depth fundamental understanding of underlying reaction mechanisms of the heterointerface and structures engineering in constructing other advanced electrodes in sustainable energy storage.

An inexpensive preparation of unique nano-micro porous LiFePO4 cathode with excellent rate capability for lithium-ion batteries

The application of LiFePO4 cathode material in the field of power lithium-ion batteries is seriously hampered by its poor rate performance that is triggered by its inherent poor electrical conductivity and low ion diffusion coefficient. Herein, an inexpensive and facile preparation method is developed to fabricate a novel nano-micro porous structural LiFePO4 cathode using 30 nm carbon black and iron powder as direct raw materials. It is found that the added amount of carbon black is an important factor affecting the phase and morphology of the products. Optimizing the amount of carbon black, the LiFePO4 cathode with the unique nano-micro porous structure and high specific surface area could be obtained. Such unique porous architecture with a high specific surface area can accelerate lithium-ion diffusion during charge/discharge to promote its rate performance. Meanwhile, the residual graphitized carbon derived from carbon black can not only enlarge the surface pseudocapacitance under high C rates but also enhance its electronic conductivity. Benefit from the suitable pseudocapacitive behavior and high Li+ diffusion coefficient, the LFP-1.5 electrode exhibits a discharge specific capacity of 166.27 mAh/g at 0.1C and 124.95 mAh/g at 20C, indicating prominent discharge specific capacity and excellent high-rate charge/discharge capability.

Super expanded freestanding 3D graphene foam as a versatile platform for CO2 capture and hydrogenation

A robust fabrication process has been developed to produce super-expanded freestanding 3D reduced graphene oxide foams (SE-rGO) with an outstanding porous architecture and stable geometry for effective capture (from the atmosphere) and the conversion of CO2 into fuel. The 3D SE-rGO foam was prepared using salicylic acid-induced exfoliation of graphene layers based on a template-assisted process. The foam was then coated with a thin layer of polydopamine (pDA) to enhance its physical and functional properties. The morphology and structural integrity of the foam were examined using SEM, XRD, XPS, and TGA. Owing to its unique 3D porous architecture and large specific surface area (767 m2/g, SSA), the foam displayed excellent multifunctional attributes, namely high CO2 adsorption capacity (4.17 mmol/g) and catalytic support for effective CO2 hydrogenation to formate. The key catalytic activity was made possible by coating the foam with palladium nanoparticles. The coated foam showed outstanding hydrogenation of CO2 to formate with a maximum yield of 24.3% at 120 °C. Given its potential, this graphene foam can be a promising and versatile material for both CO2 capture and CO2 hydrogenation.

Synthesis of Fe-doped Mn-based Prussian blue hierarchical architecture for high-performance sodium ion batteries

Sodium manganese hexacyanoferrates (MnHCFs) have great potential as cathode for sodium-ion batteries (SIBs) owing to their large specific capacity, low cost, ecofriendly synthesis and high working voltage. Nevertheless, their cycling stability is limited by Jahn-Teller effect (JT-effect) of Mn3+, phase transitions and Mn2+ dissolution during the charging and discharging processes. Herein, an unconventional solid-liquid two-phase route is developed to fabricate a novel hierarchical nanostructure Na1.02Mn0.57Fe0.43[Fe(CN)6]0.63∙1·39H2O in view of different solubility of raw material Na4Fe(CN)6·10H2O in the mixed solvent of ethanol and water. Benefiting from unique porous hierarchical architecture, good structural stability, high electrical conductivity and fast capacitive behavior, such Fe-doped MnHCF cathode has an outstanding rate capability with large discharging capacity of 127 mAh g−1 at 25 mA g−1 and 71 mAh g−1 at 1200 mA g−1, and an excellent cyclability with 120 mAh g−1 of specific capacity at 100 mA g−1 and 86% of capacity retention over 200 cycles. In particular, the facile and controllable synthesis process of Fe-doped MnHCFs make it accessible for large-scale applications.

In situ transmogrification of nanoarchitectured Fe-MOFs decorated porous carbon nanofibers into efficient positrode for asymmetric supercapacitor application

In situ transmogrification is one of the most promising ways to synthesize positrode materials using a chemical treatment approach under optimal conditions for supercapacitor applications. The nickel salt concentration plays a vital role in the complete transmogrification of Fe-MOFs@PCNFs into Ni-Fe-OH@PCNFs (positrode). Herein, we successfully transform the tetragonal Fe-MOFs@PCNFs structure into pellet-like Ni-Fe-OH@PCNFs via in situ transmogrification under fixed temperature and pressure. The obtained Ni-Fe-OH@PCNFs-1 possess a unique porous architecture with a large surface area (74.3 m2g−1), which facilitates ion relocation and electron movement within the materials during charging/discharging. Owing to the limited surface area of electroactive materials, the double transition metal hydroxides (Ni-Fe-OH@PCNFs-D) synthesized directly (i.e., by employing two metal salts instantaneously) suffer a rapid decline in capacitance during cyclic stability test. The Ni-Fe-OH@PCNFs-1 electrode generated from Fe-MOFs@PCNFs has excellent cycling stability with ~86.7% capacitance retention and ~ 91.3% coulombic efficiency after 10,000 cycles at 10 A g−1. It also exhibits a remarkable specific capacitance of 1528 F g−1 at 1 A g−1. Additionally, the asymmetric supercapacitors (Ni-Fe-OH@PCNFs-1//Fe2O3/NPC@PCNFs) exhibit a maximum energy density of 44.3 Wh kg−1 at a power density of 907 W kg−1). The results of this work suggest the possibility of using MOF-derived nanoporous electrode materials and additional transition metal hydroxides for supercapacitors.

MOF-Derived Urchin-like Co9S8-Ni3S2 Composites on Ni Foam as Efficient Self-Supported Electrocatalysts for Oxygen Evolution Reaction

Effective and inexpensive electrocatalysts are significant to improve the performance of oxygen evolution reaction. Facing the bottleneck of slow kinetics of oxygen evolution reaction, it is highly desirable to design the electrocatalyst with high activity, good conductivity, and satisfactory stability. In this work, nickel foam supported hierarchical Co9S8–Ni3S2 composite hollow microspheres were derived from in situ-generative MOF precursors and the subsequent sulfurization process by a simple two-step solvothermal method. The composite microspheres were directly grown on nickel foam without any binder, and nickel foam was used as the nickel source and support material. The morphology and constitution of the series self-supported electrodes were characterized by SEM, TEM, XRD, XPS, and Raman, respectively. The unique porous architecture enriched the electrode with sufficient active surface and helped to reactants and bubble evolved during electrochemical water oxidation. Through tuning the concentration of cobalt source and ligand, the content ratio of Co9S8 and Ni3S2 can be modulated. The heterostructures not only afford active interfaces between the phases but also allow electronic transfer between Co9S8 and Ni3S2. The optimized Co9S8-Ni3S2/NF-0.6 electrode with the highest electrochemical surface area and conductivity shows the best OER performance among the series electrodes in 1 M KOH solution. The overpotential of Co9S8-Ni3S2/NF-0.6 is only 233 mV when the current density is 10 mA cm−2, and corresponding Tafel slope is 116.75 mV dec−1. In addition, the current density of Co9S8-Ni3S2/NF-0.6 electrocatalyst hardly decreased during the 12 h stability measurement. Our approach in this work may provide the future rational design and synthesis of satisfactory OER electrocatalysts.

MnCo2O4 decorating porous PbO2 composite with enhanced activity and durability for acidic water oxidation

Developing a promising catalyst with both improved activity and robust durability for the oxygen evolution (OER) in an acidic electrolyte is extremely desirable. Here we constructed a novel MnCo2O4 decorating PbO2 electrode (3D-Ti/α-PbO2/β-PbO2-MnCo2O4) with a sandwich-like structure via a successive co-precipitation and co-electrodeposition onto porous titanium (3D-Ti) support. The experimental results indicated that the introduction of porous titanium is essential for achieving a unique porous structure architecture. In addition, the adoption of MnCo2O4 increased the contact area with electrolyte due to the large BET surface area of 144.06 cm2 g−1. Consequently, the synthesized 3D-Ti/α-PbO2/β-PbO2-MnCo2O4 composite electrode exhibited a low overpotential of 379 and 453 mV at 10 and 50 mA cm−2, respectively, as well as a minor Tafel slope of 133 mV per decade in 0.5 M H2SO4 solution. Furthermore, 3D-Ti/α-PbO2/β-PbO2-MnCo2O4 presents robust durability, keeping steady for more than 140 h at 50 mA cm−2 and without observable performance degradation, which is superior to many reported state-of-the-art non-precious OER catalysts. This route is for creating and synthesizing non-precious and superior performance catalysts for electrolysis and beyond.

MXene-reinforced octahedral PtCu nanocages with boosted electrocatalytic performance towards endocrine disrupting pollutants sensing.

Rational tailoring of hollow and porous bimetallic structures with excellent electrocatalytic performance is appealing yet challenging. Further, combining independent bimetallic nanoparticles with flexible two-dimensional substrate by forming stable heterocomplex is still highly desired for electrocatalysis. Herein, hierarchical PtCu alloy octahedrons with hollow interiors and nanosheet-assembled nanoshells were synthesized by a facile and efficient chemical transformation strategy using Cu2O as sacrificial templates. Such octahedral PtCu nanocages displayed significantly enhanced electrocatalytic activity owing to their unique hollow and porous architectures which provided easy access for analytes to the catalyst surface. Thereafter, introduction of Ti3C2Tx MXene was realized via simple incubation of Ti3C2Tx in solution containing the 3-aminopropyltriethoxysilane-capped PtCu, and their electrostatic interaction guaranteed the firm adsorption of PtCu nanocages on Ti3C2Tx nanosheets. It turned out that the sensitivity of the hybrid sensor was remarkably improved for electrochemical monitoring of endocrine disrupting pollutants in water, exhibiting ultrawide linear ranges and sub-nanomole detection limits. The eminent electrode performance is attributed to the high specific area, fast electrochemical kinetics, decent electrical catalytic ability, and the synergistic effect between Pt, Cu, and MXene.