FDCA Yield Research Articles

Effects of different vacancies in nickel hydroxides on the electrooxidation towards 5-hydroxymethylfurfural

The electrocatalytic oxidation of 5-hydroxymethylfurfural (HMFOR) emerges as an alternative pathway for the green production of valuable oxygenated chemicals owing to the catalyst innovation. The performance of nickel hydroxides, which are well-known for HMFOR, is still far from satisfactory as a result of the weak adsorption towards HMF, limited intrinsic activity and poor conductivity. Vacancy engineering provides an effective way to improve the catalytic ability of nickel hydroxides, nevertheless the role of different vacancies played in the HMFOR process is still unclear. Herein, a carbon-paper supported nickel hydroxide (Ni(OH)2/CP) with anionic vacancies (av-Ni(OH)2/CP) or cationic vacancies (cv-Ni(OH)2/CP) is employed for HMFOR study, with a special focus on the structure–function relationship between vacancy type and HMFOR performance. The successful introduction of different vacancies was manifested by electron paramagnetic resonance spectroscopy. X-ray photoelectron spectroscopy revealed the opposite roles of the anionic and cationic vacancies in modulating the electronic structure of Ni(OH)2. The time-dependent open-circuit potential measurements verified the different adsorption behavior of HMFOR on the surface of the catalysts. Benefiting from the well-tuned electronic structure and the enhanced adsorption ability, the av-Ni(OH)2/CP exhibits superior catalytic performance than the pristine Ni(OH)2/CP and the cv-Ni(OH)2/CP. More than 98.97% HMF can be converted using av-Ni(OH)2/CP as catalyst, with a remarkable yield of FDCA (98.51%) and a ultrahigh faradaic efficiency (98.46%) at 1.45 V. This work not only reports an excellent HMFOR electrocatalyst, but also elucidates the crucial effect of different vacancies on the electrochemical oxidation performance of Ni(OH)2 materials.

Oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid over CuO and NiO modified natural sourced hierarchical ZSM-5

The platform molecule 2,5-furandicarboxylic acid (FDCA) has potential applications. FDCA can be synthesized through the oxidation of 5-hydroxymethylfurfural (HMF). In this study, HMF oxidation to FDCA was conducted over ZSM-5-based catalysts from natural sources. ZSM-5 was impregnated with CuO and NiO oxide metals to increase their acidity and oxidizing ability. Characterization of the catalyst utilizing x-ray diffraction (XRD), infrared spectrophotometer (FT-IR), scanning electron microscopy-energy dispersive x-ray (SEM-EDX), Brunauer-Emmet-Teller (BET) surface area analysis, and temperature-programmed desorption of ammonia (NH3-TPD) led to the discovery of its physicochemical characteristics. The results showed that synthesized ZSM-5 had hierarchical pores with a surface area of 123.58 m2/g. Impregnation with CuO and NiO increased the acidity by 22.5 and 3.04 % for CuO/ZSM-5 and NiO/ZSM-5, respectively. In a small glass batch reactor, HMF was converted to FDCA, and the products were analyzed using High-Performance Liquid Chromatography (HPLC) to determine the yield of FDCA and the intermediate compounds, such as 5-hydroxymethylfuroic acid (HMFCA), 5-formylfuroic acid (FFCA), and 2,5-diformylfuran (DFF). HPLC results showed no DFF signal, indicating the formation of FDCA from HMF through HMFCA and FFCA. The highest conversion (99.2 %) was obtained using a NiO/ZSM-5 catalyst at a temperature of 130 °C for 4 h, with FDCA yield of 88.9 %.

Industrially Promising β‐Ni(OH)2 Nanosheets Self‐Supported Electrode for Highly Efficient Electrooxidation of 5‐Hydroxymethylfurfural

AbstractThe electrocatalytic selective oxidation of 5‐hydroxymethylfurfural (HMF) presents a highly efficient and eco‐friendly method for biomass utilization. Herein, we synthesized pure β‐Ni(OH)2 and amorphous Ni(OH)2 on nickel foam (NF) using a facile stepwise electrodeposition technique and evaluated their catalytic performances for the oxidation of HMF to 2,5‐furan dicarboxylic acid (FDCA). The β‐Ni(OH)2 nanosheets‐decorated electrode (β‐NiNS/NF) exhibited excellent interfacial lattice matching with the substrate nickel, resulting in enhanced electron transfer at the catalyst‐substrate interface, as confirmed by electrochemical analysis. Consequently, the β‐NiNS/NF electrode displayed improved intrinsic electrocatalytic activity and interfacial stability. Additionally, it demonstrated effective HMF adsorption capability. These advantageous properties led to enhanced HMF conversion, selectivity, and structural stability. Notably, the β‐NiNS/NF electrode achieved an unprecedented FDCA yield of 80.6 % under relatively large current density galvanostatic electrolysis commonly used in industry. Moreover, our investigation identified a novel possible oxidation pathway during HMF electrocatalysis. This study not only showcases an efficient and scalable synthetic approach but also highlights the potential of the β‐NiNS/NF electrode for industrial HMF electrocatalytic oxidation under conditions involving relatively large applied currents.

Oxygen Vacancy-Induced Metal-Support Interactions in AuPd/ZrO2 Catalysts for Boosting 5-Hydroxymethylfurfural Oxidation.

The construction of strong metal-support interactions in oxide-supported noble metal nanocatalysts has been considered an emerging and efficient way in improving catalytic performance in biomass-upgrading reactions. Herein, a citric acid (CA)-assisted synthesized ZrO2 layer with improved oxygen vacancy (Ov) concentrations on a natural clay mineral of halloysite nanotubes (HNTs) was designed. Moreover, AuxPdy/ZrO2@HNTs-zCA catalysts were prepared by loading AuPd bimetal and employed for aerobic oxidation of the lignocellulosic biomass-derived 5-hydroxymethylfurfural (HMF) platform to the bioplastic monomer 2,5-furandicarboxylic acid (FDCA) with water as the solvent. The results of catalytic experiments revealed that the Au3Pd1/ZrO2@HNTs-1.0CA catalyst exhibited excellent catalytic activity at 0.5 MPa O2, with a satisfactory FDCA yield of 99.5% and outstanding FDCA formation rate of 1057.9 mmol·g-1·h-1. The improved Ov concentration in the ZrO2 support enhanced the adsorption and activation ability of the catalyst for O2, and a higher Lewis acid concentration provided a stronger adsorption ability of the catalyst for reaction substrates. Besides, the synergistic effect of AuPd bimetallic nanoparticles steered the tandem oxidation of aldehyde and alcohol groups in HMF and accelerated the rate-determining step. More importantly, the relationship between the Ov concentration and catalytic performance also demonstrated that the enhanced catalytic activity for HMF oxidation was mainly attributed to the active interface of AuPd-ZrOx. This work offers fresh insights into rationally designing oxygen vacancy-driven strong interactions between the oxide support and noble nanoparticles for the catalytic upgrade of biomass platform chemicals.

Tailoring the selective adsorption sites of NiMoO by Ni particles for biomass upgrading assisted hydrogen production

5-Hydroxymethylfurfural electrooxidation reaction (HMFOR) is a promising route to produce value-added chemicals from biomass. Since it involves HMF adsorption and C–H/O–H cleavage, understanding the adsorption behavior and catalytic process of organic molecules on catalysts is important. Herein, the selective adsorption sites of NiMoO are tuned by Ni particles for HMFOR-assisted H2 production. Experimental and theoretical calculation results indicate that the synergistic interaction between Ni and NiMoO optimizes the adsorption/desorption of HMF/intermediates/2,5-furandicarboxylic acid (FDCA) and promotes the C–H/O–H bond cleavage, thereby improving the HMFOR kinetics (kNiMoO-Ni/kNiMoO = 1.97) and FDCA selectivity (99.3%). When coupled as a two-electrode system, it can drive efficient HMF conversion (FDCA yield: 98.5%) and H2 production (Faradaic efficiency: 99.1%) at 1.45 V. This work thus offers a strategy to tune the adsorption sites of catalyst for efficient HMFOR-assisted H2 production.

Strong metal-support interaction between AuPd nanoparticles and oxygen-rich defect ZrO2 for enhanced catalytic 5-hydroxymethylfurfural oxidation

The unique properties of metal oxide surfaces, crystal surfaces and defects play vital roles in biomass upgrading reactions. In this work, hierarchical porous bowl-shaped ZrO2 (HB-ZrO2) with mixed crystal phase was designed and employed as the support for loading AuPd bimetal with different proportions to synthesize AuPd/HB-ZrO2 catalysts. The effects of surface chemistry, oxygen defects, bimetal interaction and metal-support interaction of AuPd/HB-ZrO2 on catalytic performance for the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) were systematically investigated. The Au2Pd1/HB-ZrO2 catalyst afforded a satisfactory FDCA yield of 99.9% from HMF oxidation using O2 as the oxidant in water, accompanied with an excellent FDCA productivity at 97.6 mmol g−1 h−1. This work offers fresh insights into rationally designing efficient catalysts with oxygen-rich defects for the catalytic upgrading of biomass platform chemicals.

Single-atoms Ru/NiFe layered double hydroxide electrocatalyst: Efficient for oxidation of selective oxidation of 5-hydroxymethylfurfural and oxygen evolution reaction

The adsorption performance modulation of catalysts on reactants is effective for the improvement of catalytic oxidation reactions. Ru is beneficial for adsorption of products. Here, the single Ru atoms were supported on NiFe layered double hydroxide (LDH) (Ru0.3/NiFe) to enhance the adsorption capacity of catalyst using a two-step electrodeposition method. Ru0.3/NiFe was used in the oxygen evolution reaction (OER) and the selective oxidation of 5-hydroxymethylfurfural (HMFOR). Ru0.3/NiFe showed extremely low overpotential (243 mV at 10 mA cm-2) and excellent durability in OER. Ru0.3/NiFe exhibits excellent HMF conversion (99.43%), 2,5-furan dicarboxylic acid (FDCA) selectivity (99.24%) and yield (98.68%) in HMFOR. The possible HMFOR reaction pathway was further studied, revealing that the load of Ru enhances the path from HMF to DFF, thereby improving the yield of FDCA. Both the outcomes of experimental findings and density functional theory (DFT) calculations indicate that increasing the composition of Ru optimizes the adsorption energy of HMF compared to NiFe, allowing FeNiOOH to more efficiently capture protons and electrons in HMFOR.

Alkalization of acetylacetonates: A facile and versatile method to prepare Ni-based hydroxides for the electrochemical production of bio-based 2,5-furandicarboxylic acid

A facile and versatile synthesis method is required for the preparation of Ni-based hydroxides, which are efficient electrocatalysts for oxidation of 5-hydroxymethylfurfural (HMF) to high-value added chemical 2,5-furandicarboxylic acid (FDCA). Herein, a preparation strategy for Ni-based hydroxides is provided based on the alkalization of acetylacetonates. With carbon black as the support, ultrathin porous Ni(OH)2 nanosheets (∼1 nm in thickness) are obtained with HMF conversion and FDCA yield reaching ∼100% and 98.1%, respectively. With carbon felt or nickel foam as the substrate, the self-supporting Ni(OH)2 electrode can continuously operate in anion exchange membrane electrolyzer for up to 80 h with the content of FDCA in product between 80% and 100%. After the scale-up of preparation process, the performance of catalyst and electrode is maintained. Moreover, Ni-Co bimetallic hydroxide can be also prepared by this method, which presents enhanced activity for HMF oxidation at low electrode potentials.

Regulating the Electronic Structure of Ni Sites in Ni(OH)2 by Ce Doping and Cu(OH)2 Coupling to Boost 5-Hydroxymethylfurfural Oxidation Performance.

Biomass is a sustainable and renewable resource that can be converted into valuable chemicals, reducing the demand for fossil energy. 5-Hydroxymethylfurfural (HMF), as an important biomass platform molecule, can be converted to high-value-added 2,5-furandicarboxylic acid (FDCA) via a green and renewable electrocatalytic oxidation route under mild reaction conditions, but efficient electrocatalysts are still lacking. Herein, we rationally fabricate a novel self-supported electrocatalyst of core-shell-structured copper hydroxide nanowires@cerium-doped nickel hydroxide nanosheets composite nanowires on a copper mesh (CuH_NWs@Ce:NiH_NSs/Cu) for electrocatalytically oxidizing HMF to FDCA. The integrated configuration of composite nanowires with rich interstitial spaces between them facilitates fast mass/electron transfer, improved conductivity, and complete exposure of active sites. The doping of Ce ions in nickel hydroxide nanosheets (NiH_NSs) and the coupling of copper hydroxide nanowires (CuH_NWs) regulate the electronic structure of the Ni active sites and optimize the adsorption strength of the active sites to the reactant, meanwhile promoting the generation of strong oxidation agents of Ni3+ species, thereby resulting in improved electrocatalytic activity. Consequently, the optimal CuH_NWs@Ce:NiH_NSs/Cu electrocatalyst is able to achieve a HMF conversion of 98.5% with a FDCA yield of 97.9% and a Faradaic efficiency of 98.0% at a low constant potential of 1.45 V versus reversible hydrogen electrode. Meanwhile, no activity attenuation can be found after 15 successive cycling tests. Such electrocatalytic performance suppresses most of the reported Cu-based and Ni-based electrocatalysts. This work highlights the importance of structure and doping engineering strategies for the rational fabrication of high-performance electrocatalysts for biomass upgrading.

Whole-cell synthesis of 2,5-furandicarboxylic acid from pineapple waste under various fermentation strategies

2,5-Furandicarboxylic acid (FDCA) is one of the platform chemicals and monomers used in plastic industries, currently synthesized by carcinogenic and toxic chemical processes with high pressure and temperature. The aim of this study was to develop a bioprocess for the production of FDCA. 5-(Hydroxymethyl)furfural (HMF) was synthesized (22.67 ± 1.36 g/l/h) from pineapple peel using chromium(III) chloride (CrCl3) at 100 °C. After optimization, approximately 3 mg/l/h FDCA was produced by Aspergillus flavus APLS-1 from HMF in a 2.5 L fermenter in a batch strategy. Parallel and immobilized packed bad bioreactors showed less production of FDCA. A fed-batch strategy produced 3.5 ± 0.3 mg/l/h of FDCA in shake flasks. Also, approximately 0.55 mg/l/h of FDCA was produced from pineapple waste derived HMF. However, these bioprocesses may be improved to increase the yield of renewable FDCA, in the future. This is the first report on FDCA production from pineapple waste.

Turning damages into benefits: Corrosion-engineered cobalt foam for highly efficient biomass upgrading coupled with H2 generation

Electrocatalysis using 5-hydroxylmethylfurfural (HMF) as a substrate to produce 2,5-furandicarboxylic (FDCA) is a potentially sustainable and mild route to harvest both value-added chemicals and clean energy hydrogen. However, the poor chemical and thermal stability of HMF has impeded its storage and industrialization. Additionally, the uncontrollability, scalability, and cost of catalyst preparation methods are rarely considered in this field. Herein, we capitalize on the spontaneous and harmful corrosion phenomenon occurring under natural conditions to prepare efficient Co-based catalysts for the electrooxidation 2,5-bis(hydroxymethyl)furan (BHMF) with more stable dihydroxy groups, coupled with hydrogen evolution. The preparation of electrocatalysts through corrosion engineering is a straightforward, cost-effective, highly feasible, and scalable approach, requiring minimal equipment. In the optimal concentration of 200 mM BHMF, an ultrahigh current density of 1981.7 mA cm−2 was achieved at 2.293 V vs. RHE, contributed by both BHMF oxidation and oxygen evolution reaction (OER). Chronoamperometric electrolysis realized efficient FDCA production with 95.4% yield and 96.5% faradaic efficiency (FE) at an ultralow potential of 1.4 V vs. RHE. Since it is etched and grown on the substrate itself, the catalyst prepared by corrosion engineering is very stable and undergoes ten successive chronoamperometric electrolysis without significant structural or performance failure. Moreover, kinetic analyses are investigated to explore the origin of catalytic activity and reaction energy barrier. Finally, to further realize the potential of FDCA and H2 production in practical application, we innovatively designed a device with a two-electrode electrolyzer and a solar cell in series to drive BHMF electrooxidation with outdoor sunlight. The complete conversion of BHMF only takes 90 min, achieving a 93.5% FDCA yield and nearly theoretical hydrogen evolution.

Iron(III) Sulfate-Mediated Synthesis of 2,5-Furandicarboxylic Acid Dimethyl Ester from Galactaric Acid

2,5-furandicarboxylic acid (FDCA) is one of the most studied bio-based monomers, being considered the best substitute for fossil-derived terephthalic acid in plastic production. FDCA is employed in the preparation of polyethylene furanoate (PEF), demonstrating superior mechanical and thermal proprieties compared to the widely used polyethylene terephthalate (PET). Nevertheless, FDCA synthesis mostly relies on the oxidation of the bio-based platform chemical hydroxymethyl furfural (HMF), whose notoriously instable nature renders FDCA yield and industrial scale-up production complicated. On the contrary, FDCA esters are less studied, even though they have greater solubility in organic media, which would favor their isolation and potential application as monomers for PEF. On these premises, we report herein an alternative green synthetic approach to FDCA methyl ester (FDME) using galactaric acid as the substrate, dimethyl carbonate (DMC) as the green media, and Fe2(SO4)3 as the heterogeneous Lewis acid. Optimization of the reaction conditions allowed the selective production of FDME in a 70% isolated yield; product purification was achieved via flash column chromatography over silica. Furthermore, it was possible to employ up to 5.0 g of galactaric acid in a single reaction, leading to a good isolated yield of FDME.

Exfoliated Layered Metal Oxide-Supported Ruthenium Catalysts for Base-Free Oxidation of 5-Hydroxymethylfurfural into a Renewable Bioplastic Precursor

2,5-Furandicarboxylic acid (FDCA) is a potential biopolymer precursor for polyethylene furanoate production. This study focused on synthesizing FDCA via catalytic oxidation of 5-hydroxymethylfurfural (HMF) over Ru-based catalysts supported on exfoliated MgAl-double oxides (LDO) for the first time in a homogeneous base-free system. Effects of the exfoliation solvent, preparation method, and Ru loading level on the physicochemical and catalytic properties of the resulting catalysts were investigated. The exfoliated LDO-supported Ru catalysts exhibited enhanced textural properties, RuOx dispersion, and basicity, resulting in better catalytic activity (at least 6 times higher FDCA yield) than conventional LDO-supported Ru catalysts in the conversion into FDCA. The Ru-based catalyst supported on an exfoliated LDO/carbon nanocomposite, Ru(3)/ESV-LDC, revealed the nearly complete HMF conversion (99.2%) at an FDCA selectivity of >98%. This was attributed to the synergistic effect derived from good RuOx dispersion, providing a high proportion of lattice oxygen for boosting surface oxygen mobility, and high basicity, in terms of both strength and number of basic sites. Moreover, Ru(3)/ESV-LDC exhibited good reusability without a significant loss of HMF conversion and FDCA yield, suggesting strong chemical robustness of RuOx species and a stable interaction between the active metal and support.

Cu2 P7 -CoP Heterostructure Nanosheets Enable High-Performance of 5-Hydroxymethylfurfural Electrooxidation.

Electrooxidation of 5-hydroxymethylfural (HMF) into 2,5-furandicarboxylicacid (FDCA) has been regarded as a promising sustainable approach to achieve value-added chemicals. However, it is still impeded by the unsatisfactory performance of electrocatalysts. Here, Cu2 P7 -CoP heterostructure nanosheets were reported to enable powerful HMF electrooxidation. The Cu2 P7 -CoP heterostructure nanosheets were fabricated by microwave-assisted deep eutectic solvent (DES) approach, along with subsequent phosphiding. The Cu2 P7 -CoP heterostructure nanosheets enabled a superb 100 % HMF conversion at 1.43 V (vs. RHE) with 98.8 % FDCA yield and 98 % Faradaic efficiency (FE), demonstrating its promising application in HMF electrooxidation. X-ray photoelectron spectroscopy (XPS) analysis, open-circuit potential (OCP) approach and density functional theory (DFT) calculation uncovered that the electron transfer and redistribution between Cu2 P7 and CoP improved the adsorption capacity of HMF and modulated the catalytic performance. This study not only offered a powerful electrocatalyst for HMF electrooxidation, but also provided a conceptually new strategy for the heterostructure catalyst design.

Liquid flow fuel cell with an electrodeposition-modified nickel foam anode for efficient oxidation of 5-hydroxymethylfurfural to produce 2, 5-furandicarboxylic acid with co-generation of electricity

Liquid flow fuel cells were developed as reactors for efficient conversion of 5-hydroxymethylfurfural (HMF) to 2, 5-furandicarboxylic acid (FDCA) at room temperature with co-generation of electricity. Electrodeposition modification of nickel foam (NF) with CoSO4 and NaH2PO2 (Co-P@NF anode) was found to significantly increase HMF oxidation efficiency, due to the reduction of polarization resistance of NF and increased electrochemical active area. However, the active species of Co-P@NF anode for HMF oxidation actually was NiOOH rather than cobalt. By using (VO2)2SO4 as a cathodic electron carrier, peak power density of 38.9 mW/cm2 at room temperature was obtained with 100% HMF conversion and 89.0–93.4% FDCA yield. FDCA concentration reached 81.8 g/L with 90% total yield after feeding HMF for six batches. Therefore, efficient production of FDCA was achieved under mild conditions with oxygen (air) as the final oxidant via the electron transport chains constructed by active nickel species and cathode electron carriers.

CO2‐Enhanced Production and Synthesis of 2,5‐ Furandicarboxylic Acid under CO2 Flow through Henkel Reaction

AbstractThe present study investigated the preparation of 2,5‐furandicarboxylic acid (FDCA) via the Henkel reaction between furoic acid alkali metal salts and zinc chloride under a continuous CO2 flow at atmospheric pressure. The results obtained were compared with those of previous studies that used high‐pressure conditions or toxic cadmium catalysts. The pathways and rate‐determining steps of the reaction are revealed for the first time. Furthermore, the enhanced formation of FDCA through the promotion of carboxyl exchange and rearrangement during the reaction under a CO2 flow was examined. The CO2‐rich environment afforded a high FDCA yield of 86.30 %, which is the highest yield obtained to date using the Henkel reaction. The findings of this study offer economically improved conditions for large‐scale FDCA production.

Integrated Biphasic Electrochemical Oxidation of Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid

Production of biobased platform chemicals and polymers via electrochemical routes enables the direct utilization of electrical energy from renewable sources. To date, the integration of electrochemical conversions in process chains remains largely unexplored, and the reactions are often studied using synthetic solutions. This work demonstrates the biphasic electro-oxidation of hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) and couples the electrochemical oxidation with the biphasic dehydration of fructose to HMF. The integrated approach eradicates the intermediate HMF purification as the HMF-rich organic product phase is fed directly into the electrochemical flow-cell reactor. Here, HMF is extracted into the aqueous phase and oxidized to FDCA on a Ni(OH)2/NiOOH catalyst in a 0.1 M KOH solution at pH 13. The FDCA then remains in the aqueous phase, enabling direct recirculation of the HMF-containing organic phase. We demonstrate a FDCA yield of close to 80% with a feed from HMF synthesis. Further, we analyze the influence of the phase ratio (organic to aqueous) and current density for biphasic electrochemical oxidation. By adjusting the gap width, we were able to decrease the average cell voltage from 7 V down to 3 V at a current density of 30 mA cm–1. This work presents a promising integrated process for the synthesis of green platform chemicals and provides insight into biphasic solutions in electrochemical conversions.

Electronic Modulation Induced by Ni-VN Heterojunction Reinforces Electrolytic Hydrogen Evolution Coupled with Biomass Upgrade.

The renewable electricity-driven hydrogen evolution reaction (HER) coupled with biomass oxidation is a powerful avenue to maximize the energy efficiency and economic feedback, but challenging. Herein, porous Ni-VN heterojunction nanosheets on nickel foam (Ni-VN/NF) are constructed as a robust electrocatalyst to simultaneously catalyze HER and 5-hydroxymethylfurfural electrooxidation reaction (HMF EOR). Benefiting from the surface reconstruction of Ni-VN heterojunction during the oxidation process, the derived NiOOH-VN/NF energetically catalyzes HMF into 2,5-furandicarboxylic acid (FDCA), yielding the high HMF conversion (>99%), FDCA yield (99%), and Faradaic efficiency (>98%) at the lower oxidation potential along with the superior cycling stability. Ni-VN/NF is also surperactive for HER, exhibiting an onset potential of ≈0mV and Tafel slope of 45mV dec-1 . The integrated Ni-VN/NF||Ni-VN/NF configuration delivers a compelling cell voltage of 1.426V at 10mA cm-2 for the H2 O-HMF paired electrolysis, about 100mV lower than that for water splitting. Theoretically, for Ni-VN/NF, the superiority in HMF EOR and HER is mainly dominated by the local electronic distribution at the heterogenous interface, which accelerates the charge transfer and optimize the adsorption of reactants/intermediates by modulating the d-band center, therefore being an advisable thermodynamic and kinetic process.

NiCo alloy nanoparticles anchored on mesoporous Mo2N nanosheets as efficient catalysts for 5-hydroxymethylfurfural electrooxidation and hydrogen generation

Construction of highly active and stable bifunctional catalysts for 5-hydroxymethylfurfural oxidation reaction (HMFOR) and hydrogen evolution reaction (HER) is meaningful but remains a challenge. Herein, the NiCo–Mo2N heterostructure nanosheets catalyst with excellent HMFOR/HER performance is obtained by a simple hydrothermal and calcination method. The heterogeneous interface between NiCo and Mo2N induces electron redistribution, regulating the electronic structure of the catalyst and thus optimizing the adsorption/desorption behavior of HMFOR/HER intermediates. Consequently, NiCo–Mo2N/NF exhibits superior catalytic activity with a potential of 1.14 VRHE/−17 mVRHE (HMFOR/HER) at ±10 mA cm−2, and the HMF conversion rate, FDCA yield, and Faradaic efficiency (FE) are ∼100%, 99.98%, and 98.65%, respectively. Besides, it only requires a low voltage of 1.36 V to achieve 100 mA cm−2 for HMFOR-assisted H2 production. This study provides a strategy for the development of efficient bifunctional catalysts for sustainable production of high value-added products and hydrogen.

Nickel-phytic acid hybrid for highly efficient electrocatalytic upgrading of HMF.

Electrocatalytic upgrading of 5-hydroxymethylfurfural (HMF) provides a promising way to obtain both high-value-added biomass-derived chemicals and clean energy. However, development of efficient electrocatalysts for oxidizing HMF with depressed side reactions remains a challenge. Herein, we report a nickel-phytic acid hybrid (Ni-PA) using natural phytic acid as building block for highly efficient electrocatalytic oxidation of HMF to 2, 5-furandicarboxylic acid (FDCA). Due to the coordination of nickel ion and phosphate groups of phytic acid molecule, high selectivity and yield of FDCA were achieved at 1.6V vs. RHE. Besides, Ni-PA has a higher electrochemical surface area and lower charge-transfer resistance than Cu/Fe-PA, which significantly promotes the oxidation of HMF to FDCA. This work demonstrates the potential of metal-phytic acid hybrids as effective electrocatalysts for biomass valorization.