Bimetallic Nanorods Research Articles

Preparation of Co0.5Cu0.5/CNR catalyst and its performance in hydrogen production by hydrolysis of ammonia borane

Cobalt nitrate and copper nitrate was mixed to prepare solution A. Phenyldicarboxylic acid and N,N-dimethylformamide was mixed to prepare solution B. Co/Cu Lavashield skeleton series materials (Co/Cu-MIL precursors) was then synthesized by mixing the above two solution via solvothermal method. The precursor was further carbonized to produce the MOFs derivatives, i.e. bimetallic carbon nanorods (CoxCu1–x/CNR) catalysts. The morphology and composition of the catalysts were explored by SEM, TEM, XRD, XPS and other characterization means. The results showed that CoxCu1–x/CNR was successfully obtained after calcination of Co/Cu-MIL at high temperature. The activity of the catalyst was optimal when x=0.5, the solvothermal temperature of 120 °C and the calcination temperature of 650 °C. The TOF value of the Co0.5Cu0.5/CNR catalyst for the hydrolysis of ammonia borane for the production of hydrogen was 2718.21 h–1 with activation energy of 51.64 kJ/mol. The catalyst had good cyclic stability. Although the activity decreased, the conversion of AB still maintained 100% after 10 cycles.

Waste-derived Ca and Zn-based bimetallic (Ca/Zn) nanorods encapsulated chitosan-based haemostatic dressing bandage: A step towards waste to bandages

Controlling loss of blood during militant war, traumatic injury, and surgical procedures is the greatest challenge nowadays, which leads to death, thereby the necessity of hemostatic bandages. The present work focuses on the synthesis of waste-derived (WD)-Ca incorporated Zn nanorods encapsulated with chitosan polymers (CZC) to control the loss of blood as well as bacterial infection. The as-prepared CZC bandage was tested against various biochemical tests such as PBS absorption, hemolysis, adsorption of protein, platelets aggregation/adhesion, blood clotting ability, and antibacterial test assay. The data suggested that the CZC bandage has high biocompatibility, exceptional PBS absorption ability (∼1402%), platelets aggregation (∼65%) within 10 min of exposure, protein a loading ability (∼37 mg/cm2), and ∼84% blood clotting within a 1 min of exposure. Moreover, the CZC bandage effectively kills/inhibits both E. Coli and S. aureus bacteria. Therefore, the prepared CZC bandage in this study is simple, economically viable, and sustainable development.

Magnetic Fe‐Ni bimetallic oxide shell nanorods containing anti‐protein polymer segments for protein purification

AbstractIn this paper, BSA surface‐imprinted magnetic Fe‐Ni bimetallic oxide shell nanorods (m‐FeNi@MIPs@PCBMA) were prepared with the assistance of poly(3‐[[2‐(methacryloyloxy)ethyl]dimethylammonium] propionate (PCBMA) in connection with the surface‐imprinting technique. The Fe‐Ni bimetallic oxide shell layer nanorods (m‐FeNi) with magnetic responsiveness simplified the separation and recovery process of adsorbed materials. The controlled introduction of PCBMA facilitated the reduction of protein non‐specific adsorption. At the optimal encapsulation ratio of 1:0.75 (Wm‐FeNi@MIPs: WCBMA), m‐FeNi@MIPs@PCBMA could adsorb 122.98 ± 5.00 mg/g of BSA within 80 min, and the value of the imprinting factor (IF) was also increased from 1.68 (m‐FeNi@MIPs) to 3.95. In the mixed protein adsorption and real sample separation experiments, m‐FeNi@MIPs@PCBMA could selectively separate BSA. Meanwhile, after seven adsorption–desorption experiments, the loss of BSA adsorption by the imprinted nanorods was only 15.9%, which had good reusability. Therefore, m‐FeNi@MIPs@PCBMA has a broader application prospect in the field of protein separation and purification.

Self-supported Fe, Mn-co-doped NiCo2Se4 nanorods on nickel foam for enhanced electrocatalytic performance in wide pH range

Synthesizing efficient and robust catalyst can reduce the energy barrier of overall-water-splitting (OWS) and pave the way for obtaining hydrogen energy. Herein, a novel self-supported Fe, Mn-co-doped NiCo2Se4 nanorod grown on nickel foam (Fe, Mn–NiCo2Se4/NF) was hydrothermally synthesized. The bimetallic doping can regulate the electronic structure to enhance intrinsic activity, while the nanorod arrays structure increased the active sites, consequently improving catalytic activity. In addition, the binder-free electrode can strengthen conductivity and stability. Therefore, Fe, Mn–NiCo2Se4/NF presents prominent OER activity with a low overpotential of 272 mV at 100 mA cm−2. Interestingly, the newly designed catalysts realize ultra-high HER efficiency in a universal-pH range, which requires overpotentials of 187 and 179 mV in 1.0 M KOH and 0.5 M H2SO4 to reach 100 mA cm−2, respectively. The cell potential of Fe, Mn–NiCo2Se4/NF as a bifunctional catalyst is 1.699 V at 100 mA cm−2 in 1.0 M KOH with outstanding stability for at least 180 h, surpassing many state of the art catalysts reported in literature. This work concludes that the bimetallic doping, nanorod arrays, and self-supported structure are promising strategies for preparing effective and stable catalysts for the production of hydrogen energy from water splitting reactions.

Bismuth-doped manganese molybdenum bimetallic oxide nanorods as a highly efficient nitrogen reduction catalyst

Bi-doped MnMoO4 nanorods prepared by a simple hydrothermal method exhibit an excellent electrocatalytic nitrogen gas reduction performance at −0.40 V vs. RHE.

Boosting the performance of enzyme-free biosensing system with Ni–Co bimetallic nanorod anchored on macroporous carbon composites for glucose monitoring

In this study, a nickel–cobalt bimetallic nanorod-codoped macroporous carbon nanocomposite (NiCo NR/MPC) was prepared and used for glucose detection. NiCo NR was uniformly embedded into MPC scaffolds. The synergistic effect between the excellent electrocatalytic activity of NiCo NR and the remarkable conductivity of MPC carriers increased the electron transfer and the formation of numerous usable active sites. For glucose detection, the NiCo NR/MPC-glassy carbon electrode (GCE) exhibited a good linear range (0.1–831.7 μM) and a low limit of detection (0.063 μM) (S/N = 3), with a high corresponding sensitivity of 206.8 μA mM−1 cm−2. Additionally, the GCE sensor was used to detect glucose under the same test conditions; the relative standard deviation (RSD) of the sensor was 4% after 10 repeated measurements. This indicated the reproducibility of the constructed NiCo NR/MPC-GCE sensor. Therefore, the constructed NiCo NR/MPC glucose electrochemical sensor has good application prospects.

Vertical graphene nanosheets as interface current-collector for enhanced charge-storage kinetics of bimetallic MOF nano-rods and asymmetric solid-state supercapacitors

Vertical graphene nanosheets (VGN), also known as vertical-oriented graphene or carbon nanowalls emerge recently for different energy storage devices by virtue of their interesting properties that enable them to bring out as excellent current-collector and templates for the growth of different nanostructures. In the current research, we design the facile synthesis of nano-sized bimetallic NiCo MOF on VGN (NiCo MOF/VGN) to achieve improved storage performance. The enhanced capacitive contribution, wetting nature, and charge-transfer kinetics of NiCo MOF/VGN facilitate an increase in the energy-storage performance in the case of an in-situ (solvothermal) method than the drop-cast method. Further, the comparison also confirms that VGN acts as an excellent current collector for NiCo MOF than carbon paper. Due to the unique morphology of VGN and nano rod-like NiCo MOF structure, the NiCo MOF/VGN composite delivers a specific capacity of 132 mA h g−1 (475 C g−1) and a specific capacitance of 950 F g−1 at 1 A g−1 with a high rate capability of 93.2 % at 10 A g−1. Moreover, the assembled asymmetric solid-state supercapacitor device (NiCo MOF/VGN//PVA + KOH//activated carbon) exhibited a high energy density of 58.1 Wh kg−1 at a power density of 1170 W kg−1 and a high power density of 7 kW kg−1 at an energy density of 36.5 Wh kg−1 with a cycle stability of 88.5 % after 10,000 cycles of charge-discharge.

Designing oxygen vacancy rich mesoporous CeO2 nanorods with co-doped Cd and Ni for synergistic oxidative‑hydrogenation desulfurization of transportation fuel oils

Photocatalytic oxidative coupled in situ hydrogenation is an emerging and alternative route to the traditional costly hydrodesulfurization strategy for the eradication of organosulfur compounds from transportation fuels under mild operating conditions. In this study, Cd/Ni-doped CeO2 catalysts were prepared by improved hydrothermal method, and were in turn applied for the ultra-deep desulfurization of highly resilient 4,6-dimethyldibenzothiophene (4,6-DMDBT) from diesel oil under visible light irradiation. The prepared photocatalyst were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, Fourier transform infra-red (FTIR) spectroscopy, ultra-violet visible (UV–vis) spectroscopy and Brauner-Emmette-Teller (BET) analyses. Characterization results revealed that bimetallic doped CeO2 mesoporous nanorods were of uniform size (length: 100–200 nm and width: 30–40 nm) having different oxygen vacancies. Catalytic activity evaluation results revealed that under visible light irradiation, 20%Cd/Ni@CeO2 achieved 100% desulfurization performance of 4,6-DMDBT within 50 min at 60 °C, thus surpassing many state of the art catalysts reported in literature. Cd/Ni@CeO2 remained highly active after 10 successive reuses with rapid recovery by simple washing and filtration. Based on the experimental and characterization results, a suitable reaction mechanism was speculated for the photocatalytic desulfurization of 4,6-DMDBT using Cd/Ni@CeO2.

A coactive performance of Ag2WO4 nanorods wreathed on the N-doped carbon nanofibers as electrode for electrochemical supercapacitors

The thriving energy demand of the gradually increasing population and modernised life style requires development in energy storage devices for usage in commercial electronic devices. In this particular work, we have explored electrochemical performances of bimetallic oxide Ag2WO4 nanorods and tuned its performance by decorating it on the nitrogen doped carbon nanofiber (N-CNF). The Ag2WO4 nanorods are synthesised by a facile route of co-precipitation method followed by ultrasonication with N-CNF. The synthesised Ag2WO4 nanorods was found electrochemically active and the incorporation of N-CNF end up boosting its electrochemical performances. The obtained nanocomposites were characterised by various advanced techniques. The amount of N-CNF was determined by characterisation via the potentiostatic and galvanostatic cycle measurements and electrochemical impedance spectroscopy (EIS). The electrochemically active Ag2WO4 with 20 wt. % of N-CNF (Ag2WO4/N-CNFb) exhibited 2.2-fold higher charge storage capacity than pristine Ag2WO4. The Ag2WO4/N-CNFb exhibited specific capacitance as high as 330 F g-1 at a constant applied current density of 1 A g-1 in 1 M KOH. The improved capacity may be due to conductive pathways provided by N-CNF. The Ag2WO4 got well decorated over the N-CNF facilitating the active sites interaction with electrolyte. The symmetric device fabricated with Ag2WO4/N-CNFb electrodes exhibited excellent energy density of 10 W h kg-1 at 6000 W kg-1 at 5 A g-1. The Ag2WO4/N-CNFb electrode long-term stability has been minutely observed; the high Coulombic efficiency of 90% and high rate of capacity retention 98% even after 3000 cycles. Owing to these excellent electrochemical properties, the research work can potentially widen the opportunity to explore other profound bimetallic oxides and its nanocomposites with conductive carbon-based matrix for energy storage applications.

Antibacterial activity of multi-metallic (Ag–Cu–Li) nanorods with different metallic combination ratios against Staphylococcus aureus

ObjectiveBecause of the need to extensively study the synergistic activity of metallic nanoparticles, this study aimed to evaluate the antibacterial activity of mixed metallic nanoparticles, made by differing the weight mixing ratio. We prepared multi-metallic nanorods (NRs) by chemical reduction method, with different ratio combinations of silver Ag and copper Cu, two main batches of nanorods were produced: bimetallic mix made only of Ag–Cu, and trimetallic mix made of Ag–Cu and lithium Li, AgCu NRs and AgCuLi NRs respectively. NaOH was used in the synthesis for the co-reduction of salt precursors. Ag percentage was varied from 10 to 90% in bimetallic NRs but in the trimetallic NRs, which has a fixed ratio of Li (10%), the percentage of silver precursor was from 10 to 80%. The presence of metals was confirmed by energy dispersive X-rays (EDX) analysis. Ion release was detected using inductively coupled plasma spectrometer (ICP) and the values showed that NRs are effective source for ion supply for up to 24 h. The antibacterial activity of metallic NRs was tested against Staphylococcus aureus using Bauer Kirby method.ResultsThe bi-synergistic mix of Ag and Cu generates more ions than the tri-synergistic mix of Ag, Cu, and Li. Nevertheless, the later was more efficient and showed higher antibacterial activity at lower concentrations. This effect is less likely to be attributed to modality of ion release. Indeed, the results of our work suggest that besides ion release, alloyed nanorods themselves are toxic and the trimetallic mix exhibited more biocidal activity, specifically at Ag salt concentrations of 30%, 50% and 70%.

Ultrasensitive detection of thiram based on surface-enhanced Raman scattering via Au@Ag@Ag core/shell/shell bimetallic nanorods.

We developed a highly sensitive and stable SERS-active substrate of Au@Ag@Ag core/shell/shell nanorods, formed by encapsulating Au nanorods (Au NRs) into a bilayer silver shell with Raman reporter molecules (4-mercaptobenzoic acid (4-MBA) and thiram) in the shell-shell gap. The core/shell/shell nanostructures demonstrated a high SERS enhancement and easy assembly. The important role of the bilayer silver shell in boosting the SERS intensity and detection sensitivity was revealed by comparing the performances of the Au@Ag@4-MBA@Ag NRs, Au@Ag@4-MBA NRs, and Au@4-MBA NRs. The obtained Au@Ag@4-MBA@Ag NRs exhibited a significantly promoted SERS intensity, which could reach around 2.6 times and 240 times that of the Au@Ag@4-MBA NRs and Au@4-MBA NRs, where the enhancement factor was found to be strongly correlated with the shell thickness. The controllable plasma properties and SERS effect of the Au@Ag@4-MBA@Ag NRs could be optimized by adjusting the dose of silver nitrate. The SERS substrate comprising core/shell/shell nanorods was highly reproducible and stable (retaining 83% SERS intensity after one month). Moreover, the highly sensitive detection of the pesticide thiram with a detection limit as low as 1.74 × 10-9 M was achieved by taking advantage of the great SERS response of the core/shell/shell nanostructures, which was 1-2 orders of magnitude lower than for other SERS substrates. The developed SERS substrate could be readily extended to embed other target analytes into the core/shell/shell nanostructure for novel and sensitive detection. This study could enable fresh approaches toward next-generation ultrasensitive analyte detection.

Synthesis of bone-shaped Au–Ag2S metal-semiconductor nanorods and their photocatalytic application

In this work, we describe an aqueous synthetic strategy for producing bone-shaped Au − Ag2S metal-semiconductor hybrid nanorods. Specifically, Au nanorods were first synthesized and used as seeds to synthesize bone-shaped Au − Ag nanorods by selectively overgrowing Ag shells at both ends of Au nanorods. Through the site-selective sulfidation strategy using Na2S aqueous solution, the Au − Ag bimetallic nanorods were transformed into Au–Ag2S metal–semiconductor hybrid nanorods. When used as photocatalysts for the photooxidative degradation of methylene blue (MB) under sunlight irradiation, the Au–Ag2S hybrid nanorods showed excellent photocatalytic performance due to the synergistic action of metal and semiconductor components.

NIR-induced improvement of catalytic activity and antibacterial performance over AuAg nanorods in Rambutan-like Fe3O4@AgAu@PDA magnetic nanospheres

Pathogenic bacteria and difficult-to-degrade pollutants in water have been serious problems that always plague people. Therefore, finding a “one stone-two birds” method that can quickly catalyze the degradation of pollutants and show effective antibacterial behavior become an urgent requirement. This work reports a facile one-step strategy for fabricating a Rambutan-like Fe3O4@AgAu@PDA (Fe3O4@AgAu@Polydopamine) core/shell nanosphere with both catalytic and antibacterial activities which can be critically improved by externally applying an NIR laser irradiation (NIR, 808 nm) and a rotating magnetic field. Typically, the Rambutan-like Fe3O4@AgAu@PDA nanosphere have a rather rough surface due to the AuAg bimetallic nanorods sandwiched between the Fe3O4 core and the PDA shell. Owing to the penetrated PDA shell, AgAu nanorods show high and magnetically recyclable photothermal-enhanced catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol and they can also be applied to initiate TMB oxidation under the help of NIR heating condition. Moreover, Fe3O4@AgAu@PDA shows a moderate antibacterial activity due to the weak release of Ag+. Under applying a rotating external magnetic field, the rough-surface Fe3O4@AgAu@PDA nanospheres produce a controllable magnetolytic force on the bacterial due to their good affinity. As a result, the Fe3O4@AgAu@PDA nanospheres show a "magnetolytic-photothermal-Ag+" synergistic antibacterial behavior against E. coli and S. aureus.

Single-Particle Insights into Plasmonic Hot Carrier Separation Augmenting Photoelectrochemical Ethanol Oxidation with Photocatalytically Synthesized Pd-Au Bimetallic Nanorods.

Understanding the nature of hot carrier pathways following surface plasmon excitation of heterometallic nanostructures and their mechanistic prevalence during photoelectrochemical oxidation of complex hydrocarbons, such as ethanol, remains challenging. This work studies the fate of carriers from Au nanorods before and after the presence of reductively photodeposited Pd at the single-particle level using scattering and emission spectroscopy, along with ensemble photoelectrochemical methods. A sub-2 nm epitaxial Pd0 shell was reductively grown onto colloidal Au nanorods via hot carriers generated from surface plasmon resonance excitation in the presence of [PdCl4]2-. These bimetallic Pd-Au nanorod architectures exhibited 14% quenched emission quantum yields and 9% augmented plasmon damping determined from their scattering spectra compared to the bare Au nanorods, consistent with injection/separation of intraband hot carriers into the Pd. Absorbed photon-to-current efficiency in photoelectrochemical ethanol oxidation was enhanced 50× from 0.00034% to 0.017% due to the photodeposited Pd. Photocurrent during ethanol oxidation improved 13× under solar-simulated AM1.5G and 40× for surface plasmon resonance-targeted irradiation conditions after photodepositing Pd, consistent with enhanced participation of intraband-excited sp-band holes and desorption of ethanol oxidation reaction intermediates owing to photothermal effects.

Cellphone-based attomolar tyrosine sensing based on Kollidon-mediated bimetallic nanorod in plasmon-coupled directional and polarized emission architecture

In the past decade, various interfacial materials have been explored for better sensor performance in nanoplasmonics. Despite gold being an ideal candidate for many plasmonic applications, its use in the field of surface plasmon-coupled emission (SPCE) platform is limited due to its inherent quenching phenomenon. Different methodologies have been reported to circumvent this limitation, albeit compromised by complex requirements. Moreover, the SPCE enhancement obtained hitherto remains inadequate and the use of biocompatible and eco-friendly sustainable methods in this direction has been rare. In this perspective, here we demonstrate a frugal and bio-friendly technique using ubiquitously available co-polymer kollidon® to obtain silver (Ag)-gold (Au) nanohybrids. The methodology involved is a simple, user-friendly and economical UV-induced one-pot green synthesis of hybrid architectures. The nanoparticles and nanohybrids obtained through this method were studied in three different nanointerfaces, namely: spacer, cavity and extended (ext.) cavity. Dequenched as well as in excess of 1000-fold enhancement in fluorescence was obtained in the ext. cavity nanointerface on account of hybrid plasmonic resonances. In addition to this, attomolar sensitivity was achieved for biologically important amino acid, tyrosine using a mobile phone-based detection technique. The methodology reported in this work provides a straightforward technique to obtain nanohybrids that can be used to dequench the otherwise quenched emission with new physicochemical insights, in addition to providing ample opportunities for development of next-gen mobile phone based hazardous analyte detection platforms using sustainable methodologies.

Novel Dual-Signal Electrochemiluminescence Aptasensor Involving the Resonance Energy Transform System for Kanamycin Detection.

Based on luminol-capped Pt-tipped Au bimetallic nanorods (NRs) (L-Au-Pt NRs) as the anode emitter and SnS2 quantum dots (QDs) hybrid Eu metal organic frameworks (MOFs) (SnS2 QDs@Eu MOFs) as the cathode emitter, a dual-signal electrochemiluminescence (ECL) platform was designed for the ultrasensitive and highly selective detection of kanamycin (KAN). Using a dual-signal output mode, the ratiometric ECL aptasensor largely eliminates false-positives or false-negatives by self-calibration in the KAN assay process. To stimulate the resonance energy transform (RET) system, the KAN aptamer and complementary DNA are introduced for conjugation between the donor and acceptor. With the specific recognition of target KAN by its aptamer, L-Au-Pt NRs-apt partially peels off from the electrode surface. Eventually, the RET system is removed, leading to an increasing cathode signal and a decreasing anode signal. In view of this phenomenon, the ratiometric aptasensor can quantify KAN from 1 pM to 10 nM with a low detection limit of 0.32 pM. This dual-signal ECL aptasensor exhibits great practical potential in environmental monitoring and food safety.

Conductive NiCo bimetal-organic framework nanorods with conductivity-enhanced electrochemiluminescence for constructing biosensing platform

Metal-organic frameworks (MOFs) has recently attracted immense attention in electrochemiluminescence (ECL) field, yet the ECL performance of MOFs is largely limited by their natively poor electric conductivity (generally < 10−8S m−1). To address this drawback, we adopted the doping strategy to synthesize a conductive bimetallic MOF nanorod [NixCo9-x(HHTP)4(H2O)30] (denoted as NiCo-HHTP, HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) with excellent electrical conductivity (1.20 × 10−3S m−1), which could accelerate the charge transport and facilitate the electrochemical activation of HHTP luminophore, thereby improving utilization ratio of ECL luminophores to achieve a strong ECL emission. As expected, our experiment showed that the bimetallic NiCo-HHTP was superior to the isostructural monometallic MOF (Ni-HHTP) with nearly 2.82-fold higher electrical conductivity, 2.06-fold higher ECL intensity and 3.39-fold higher ECL efficiency. These results suggested that the electrical conductivity of NiCo-HHTP could be significantly improved by doping with cobalt, and the outstanding electrical conductivity greatly contributed to its excellent ECL performance. Considering the above-mentioned superior ECL properties, the NiCo-HHTP nanorods were utilized to fabricate an ultrasensitive ECL biosensor for microRNA-141 determination, achieving a wide linear range from 1 fM to 10 nM and a low detection limit of 0.69 fM. Overall, our work proposed a hopeful and practicable strategy to improve ECL performance via enhancing electrical conductivity of MOFs, which overcame current limitation of ECL enhancement in nonconductive MOFs and opened a new chapter to prepare high-efficiency MOF-based ECL materials, thus providing a unique opportunity for constructing ultrasensitive ECL sensors.

Synthesis of reduced graphene oxide incorporated bimetallic (Cu/Bi) nanorods based photocatalyst materials for the degradation of gallic acid and bacteria

Gallic acid (GA) is a polyphenols compound commonly present inwastewater that immensely affects aquatic and human life. GA is also responsible for the inhibitory effects on the microbial activity in the soil, thereby decreasing the fertility of the soil. Therefore, the removal of GA from the wastewater is necessary to combat such issues. The present study focused on the synthesis of reduced graphene oxide (r-GO) incorporated bimetallic (Cu/Bi) based nanorods (r-GO-Cu/Bi-NRs) and their photocatalytic applications. Incorporating GO within the CuBi2O4-NRs might decrease the bandgap value, thereby increasing the interfacial charge transfer. Moreover, GO increased the reactive sites and oxygen defects onto the r-GO-Cu/Bi-NRs that led to the separation rate of the photo-induced charge carriers and migration, thereby enhancing the photodegradation ability of the synthesized r-GO-Cu/Bi-NRs. Thesynthesis process of the r-GO-Cu/Bi-NRs is facile, novel, and economically viable for the photocatalytic degradation of organic pollutants.

Mixed Metal Fe2Ni MIL-88B Metal-Organic Frameworks Decorated on Reduced Graphene Oxide as a Robust and Highly Efficient Electrocatalyst for Alkaline Water Oxidation.

The development of cost-effective and efficient oxygen evolution reaction (OER) catalysts has found increasing popularity due to the sluggish kinetics of OER, which has hampered the H2 production by H2O electrolysis. In this study, Fe2Ni MIL-88 (denoted FeNi) was composited by reduced graphene oxide (rGO, denoted R). Owing to the high porosity and abundant active sites of bimetallic MOF, proper conductivity of rGO, and the synergistic impact of Ni and Fe, the optimal composite (R@FeNi (1:1)) offered remarkable OER activity in alkaline environments. The obtained composite was employed in the OER, which led to a low overpotential of 264 mV at a current density of 10 mA cm-2 with a Tafel slope of 62 mV dec-1. Also, the bimetallic Fe2Ni MIL-88 nanorods grown on rGO led to a reduction in the onset potential of the OER. These findings exceeded the results of standard IrO2-based catalysts; they are also comparable or even better than the previously reported MOF-based catalysts.

Piezo-phototronic effect boosted catalysis in plasmonic bimetallic ZnO heterostructure with guided fermi level alignment

High photo-induced carriers (PCs) recombination rate, low PC mobility, and limited solar energy utilization rate are the three main roadblocks that severely limit the photocatalytic activity of semiconductors. In this work, we designed a plasmonic bimetallic ZnO nanorod array (Au/ZnO/Pt) with Au nanoparticles (NPs) located on top of ZnO nanorods and Pt NPs evenly distributed on the ZnO nanorods for improving catalysis through the piezo-phototronic effect. With the rational design of guided Fermi level alignment, the photoinduced hot electrons of Au NPs with localized surface plasmon resonance effect can transfer to Pt NPs through ZnO to promote the separation and migration of PC. More importantly, under the stimulation of ultrasound, ZnO with piezo-phototronic effect generates an interfacial piezo-potential, thereby further promoting the separation and transport of carriers in compliance with the direction of piezo-potential to promote the surface redox reaction. Under the synergy of piezo-phototronic effect and localized surface plasmon resonance effect, the Au/ZnO/Pt realized 97.5% dye degradation in 60 min, which was 1.2, 1.36, and 1.79 folds of that with Au/ZnO/Au, Pt/ZnO/Pt, and ZnO, respectively. The unique plasmonic bimetallic heterostructure with piezo-phototronic effect and guided Fermi level alignment can guide the directional migration of carriers and provides useful instruction for the design of high-efficiency catalysts.