Glycerol Electrooxidation Research Articles

One-pot synthesis of 2D-Ni-MOF from waste PET plastic in aqueous medium for selective electrooxidation of glycerol, ethanol, and methanol

This study investigates the electrochemical performance and selectivity of a nickel-based metal-organic framework (Ni-MOF) catalyst synthesized from waste PET plastic using a one-pot approach in aqueous media. The Ni-MOF electrode was evaluated for glycerol electrooxidation reaction (GEOR), ethanol electrooxidation reaction (EEOR), and methanol electrooxidation reaction (MEOR). Linear sweep voltammetry (LSV) revealed current densities of 30mA/cm² at 0.5639V for GEOR, 50.07mA/cm² at 0.35V for EEOR, and 45.73mA/cm² at 0.39V for MEOR, indicating superior catalytic activity. Nyquist plots showed lower charge transfer resistance (Rct) values of 11.0 Ω for GEOR, 2.79 Ω for EEOR, and 2.69 Ω for MEOR, confirming efficient electron transfer. Bode impedance plots demonstrated lower impedance for alcohol electrooxidation compared to oxygen evolution reaction (OER). Chronoamperometry (CA) tests indicated excellent stability with 75.72% glycerol conversion for GEOR and selectivities of 94% for glyceric acid, 65.59% for acetic acid in EEOR, and 70.54% for formic acid in MEOR. These results highlight the potential of Ni-MOF derived from recycled PET plastic for sustainable and efficient electrooxidation of C1-C3 alcohols.

High-valence molybdenum doped Ni(OH)2 nanosheets enhancing hydrogen production and glycerol oxidation to formic acid

The glycerol electrooxidation reaction (GEOR) replacing the anodic oxygen evolution reaction (OER) in water splitting is an effective strategy for hydrogen production and high value-added chemicals in an energy-saving manner in recent years. The key to this technology is to design efficient electrocatalysts to enhance the GEOR activity and effectively regulate product selectivity. Herein, a high-valence metal Mo-doped Ni(OH)2 nanosheets (Mo-Ni(OH)2/NF) was in-situ grown on the nickel foam (NF) for enhancing hydrogen production and glycerol oxidation to formic acid. The Mo-Ni(OH)2/NF exhibits unique network nanosheet morphology with large specific surface area and electron conduction, which is beneficial for exposing more active sites for reactions and promoting the mass transfer of electrolytes and products. The synergistic interaction between Mo and Ni facilitates the regulation of the electronic structure of the catalyst, and accelerates the reaction kinetics. When the Mo-Ni(OH)2/NF−1 is assembled into an overall glycerol-water splitting system, a low voltage of only 1.36 V is required to achieve a current density of 10 mA cm−2, which is 290 mV lower than the cell voltage needed for traditional water splitting under the same conditions.

A 2D/3D hierarchical hybrid enables energy-saving hydrogen production coupled with glycerol and urea electro-oxidation

The design and development of high-performance electrocatalysts is crucial to improve the utility of anodic reaction for energy-saving hydrogen production. Herein, we present a novel catalyst with 2D/3D multistage structure for the electro-oxidation of renewable biomass and harmful waste to assist hydrogen generation. The hierarchical configuration of NiO/CoO nanosheets interconnected by hollow carbon spheres, leveraging both 2D and 3D advantages. This structure provides rich surface and edge active sites as well as affluent electron and mass transfer pathways, resulting in the accelerated dynamics of electro-oxidation. The hollow carbon spheres serve as a buffering agent to alleviate the strain caused by repetitive redox reactions during electrolysis, thereby bestowing exceptional structural and chemical stability for prolonged operational durability. Additionally, the multiple continuous hetero-interfaces between NiO and CoO, NiO and carbon as well as CoO and carbon can ensure the fast electron transport, leading to the expedited reaction kinetics with the synergistic effect of phase engineering between NiO, CoO and carbon shell. As a result, the 3D carbon shells jointed 2D NiO/CoO hybrids demonstrate promising catalytic activities on electro-oxidation for energy-efficient hydrogen production (∼100 %FE) coupled with urea oxidation and formic acid synthesis with excellent selectivity (95.40 %) and satisfied faradic efficiency (91.6 %).

NH4Cl-Assisted Electrosynthesis of P-Doped Co(OH)2 Nanosheet on Cu2S Hollow Nanotube Arrays for Glycerol Electrooxidation.

The glycerol oxidation reaction (GOR) for producing high-value-added organic compounds is of great research interest due to its potential in alleviating the energy crisis. Herein, a facile NH4Cl-assisted electrodeposition strategy is reported to fabricate 3D nano-forest array-like hollow nanostructures. The hierarchical heterojunction by combining phosphorus doping Co(OH)2 nanosheets with Cu2S nanotube arrays (P-Co(OH)2@Cu2S NTs/CF) is developed to realize the optimization on GOR. The optimized P-Co(OH)2@Cu2S NTs/CF catalyst exhibits an exceptional activity with a formate Faradaic efficiency (FE) of 97.40% at a potential of 1.30V (vs RHE). The experimental results indicate that this unique hollow nano-forest structure, grown on a conductive support, can expose more active sites and facilitate electron transfer, thereby demonstrating excellent GOR performance. This work provides new opportunities for the design of electrocatalysts of high-activity and low-cost hollow heterostructure electrocatalysts for glycerol electrooxidation.

Combining Bismuth Telluride and Palladium for High Efficiency Glycerol Electrooxidation.

Designing high-performance anodic catalysts to drive glycerol oxidation reaction (GOR) is essential for advancing direct alcohol fuel cells. Coupling Pd with oxophilic materials is an effective strategy to enhance its intrinsic catalytic activity. In this study, we successfully synthesized Pd/Bi2Te3 catalysts with tunable compositions, using Bi2Te3 as a novel promoter, and applied them to the GOR for the first time. Electrocatalytic tests revealed that the activity of the Pd/Bi2Te3 catalysts was closely linked to their compositions. Among these catalysts, the optimized Pd/Bi2Te3-20 % showed potential to replace the commercial Pd/C catalyst, exhibiting a peak current density 5.2 times higher than that of the benchmark Pd/C catalyst. Furthermore, improved catalytic stability and faster catalytic kinetics were observed for Pd/Bi2Te3-20 %. The synergistic effect between Pd and Bi2Te3 is responsible for the high performance of the Pd/Bi2Te3-20 % catalyst.

Evaluation of Active Oxygen Species Derived fromWater Splitting for ElectrocatalyticOrganic Oxidation.

Active oxygen species (OH*/O*) derived from water electrolysis are essential for the electrooxidation of organic compounds into high-value chemicals, which can determine activity and selectivity, whereas the relationship between them remains unclear. Herein, using glycerol (GLY) electrooxidation as a model reaction, we systematically investigated the relationship between GLY oxidation activity and the formation energy of OH* (ΔGOH*). We first identified that OH* on Au demonstrates the highest activity for GLY electrooxidation among various pure metals, based on experiments and density functional theory, and revealed that ΔGOH* on Au-based alloys is influenced by the metallic composition of OH* coordination sites. Moreover, we observed a linear correlation between the adsorption energy of GLY (Eads) and the d-band center of Au-based alloys. Comprehensive microkinetic analysis further reveals a volcano relationship between GLY oxidation activity, the ΔGOH* and the adsorption free energy of GLY (ΔGads). Notably, Au3Pd and Au3Ag alloys, positioned near the peak of the volcano plot, show excellent activity, attributed to their moderate ΔGOH* and ΔGads, striking a balance that is neither too high nor too low. This research provides theoretical insights into modulating active oxygen species from water electrolysis to enhance organic electrooxidation reactions.

Evaluation of Active Oxygen Species Derived from Water Splitting for Electrocatalytic Organic Oxidation

AbstractActive oxygen species (OH*/O*) derived from water electrolysis are essential for the electrooxidation of organic compounds into high‐value chemicals, which can determine activity and selectivity, whereas the relationship between them remains unclear. Herein, using glycerol (GLY) electrooxidation as a model reaction, we systematically investigated the relationship between GLY oxidation activity and the formation energy of OH* (ΔGOH*). We first identified that OH* on Au demonstrates the highest activity for GLY electrooxidation among various pure metals, based on experiments and density functional theory, and revealed that ΔGOH* on Au‐based alloys is influenced by the metallic composition of OH* coordination sites. Moreover, we observed a linear correlation between the adsorption energy of GLY (Eads) and the d‐band center of Au‐based alloys. Comprehensive microkinetic analysis further reveals a volcano relationship between GLY oxidation activity, the ΔGOH* and the adsorption free energy of GLY (ΔGads). Notably, Au3Pd and Au3Ag alloys, positioned near the peak of the volcano plot, show excellent activity, attributed to their moderate ΔGOH* and ΔGads, striking a balance that is neither too high nor too low. This research provides theoretical insights into modulating active oxygen species from water electrolysis to enhance organic electrooxidation reactions.

Ozone-Assisted Cu-Based Catalysts for the Efficient Electro-Reforming Glycerol to Formic Acid.

Glycerol electrooxidation reaction (GOR) to produce value-added chemicals, such as formic acid, could make more efficient use of abundant glycerol and meet future demand for formic acid as a fuel for direct or indirect formic acid fuel cells. Non-noble metal Cu-based catalysts have great potential in electro-reforming glycerol to formic acid. However, the high activity, selectivity and stability of Cu based catalysts in GOR cannot be achieved simultaneously. Here, we used ozone-assisted electrocatalyst to convert glycerol to formic acid under alkaline conditions, the onset potential was reduced by 60 mV, the Faraday efficiency (FE) reached 95 %. The catalyst has excellent stability within 300 h at the current density of 10 mA cm-2. The electron spin resonance proved that ozone produced superoxide anion during the GOR. In situ Raman spectroscopy, electrochemical studies showed that glycerol can be activated with ozone in GOR, and the C-C bond can be broken to reduce the polymerization of glycerol on the catalyst surface, so as to produce more formic acid at a lower voltage. Moreover, the removal of dissolved O3 from water can be up to 100 % after 30 minutes of GOR reaction at a solubility of 50 mg L-1 as measured by UV-VIS spectrophotometry.

Super-hydrophilic and expanded graphite foil as support for Pd-Co electrodeposition: An effective catalyst for glycerol electrooxidation and HWE application

Super-hydrophilic and expanded graphite foil as support for Pd-Co electrodeposition: An effective catalyst for glycerol electrooxidation and HWE application

Converting Energy with Glycerol and CO2 in a Microfluidic Fuel Cell Equipped with CuBiO4/CuO Photocathode: Bypassing Bubbles Challenge of Concurrent Water Splitting.

The imperative to address CO2 emissions has prompted the search for alternative approaches to capture this gas with minimal energy consumption. In this context, leveraging the CO2 reduction reaction (CO2RR) as an oxidant in fuel cells has emerged as a sophisticated strategy to convert this gas into usable energy. This study introduces a hybrid microfluidic photo fuel cell (μPFC) designed for the efficient conversion of CO2 and glycerol into electrical energy. The prototype integrates 3D-printed components with glass sealing, enabling precise control over the reactant flow and the use of light-sensitive catalysts. The anodic glycerol electrooxidation was investigated on Pt/C dispersed on carbon paper (CP), while the CO2RR was carried out on CuBiO4/CP and CuBiO4/CuO/CP in the presence of solar light. Half-cell measurements demonstrate the photoactivity of CuBiO4/CuO/CP and CuBiO4/CP electrodes for the CO2RR under light exposure at low onset potential in a neutral pH solution, generating a positive theoretical open-circuit voltage of 0.89-0.91 V when coupled to glycerol electrooxidation in an alkaline medium. The use of the mixed medium in the membraneless system equipped with the photosensitive catalysts allowed the building of this galvanic cell. However, the feasibility of using CuBiO4/CP is hindered by the disruption of the colaminar channel caused by hydrogen bubbles produced during concurrent water splitting. In contrast, the μPFC equipped with a CuBiO4/CuO/CP photocathode demonstrates a stable and reproducible performance, delivering a maximum power density of 0.9 mW cm-2. The formation of the CuBiO4/CuO heterojunction effectively suppresses photocatalytic water splitting, allowing for efficient CO2 conversion without disruption of the laminar flow channel. This innovative approach highlights the potential of μPFCs as sustainable energy converters for the utilization of CO2 in aqueous solutions, offering a pathway toward carbon-neutral energy production.

Improving Glycerol Electrooxidation Performance on Nanocubic PtCo Catalysts.

As glycerol (GLY) has emerged as a highly functional and cheap platform molecule and as an abundant biodiesel production byproduct, possible conversion methods have been investigated. One of the promising approaches is the glycerol electrooxidation (GEOR) on noble metal-based catalysts. Although noble metals, especially Pt, are generally very stable at different pH and highly selective toward three-carbon (C3) products, their electrocatalytic performance can be further improved by morphology tuning and alloying with non-noble metals like Co. In the present study, cubic PtxCo100-x (x = 100, 80, and 60) nanoparticles were investigated in an alkaline medium at 20 and 40 °C. The effect of the composition and reaction conditions on the selectivity of the GEOR toward C3 products like lactate and glycerate was studied, and the reaction mechanism was discussed. The highest mass activity was found for Pt80Co20, although when the specific activity, glycerol conversion, and GEOR selectivity were compared, Pt60Co40 was the superior catalyst overall. In general, all catalysts, even those that are Co-rich, exhibited a high C3 product selectivity up to 95% at 0.67 V vs RHE. The low applied potential of 0.67 V vs RHE at 40 °C facilitated lactate formation with selectivity up to 72%. At the same time, the glycerate formation with a selectivity of up to 40%, as well as C-C bond cleavage, was more favored at 0.87 V vs RHE.

Efficient Electrocatalytic Oxidation of Glycerol to Formate Coupled with Nitrate Reduction over Cu-Doped NiCo Alloy Supported on Nickel Foam.

Electrooxidation of biomass-derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value-added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high-efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu-NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu-NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm-2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII-OOH and CoIII-OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu-NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long-term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass-derived electrochemical refinery.

Efficient Electrocatalytic Oxidation of Glycerol to Formate Coupled with Nitrate Reduction over Cu‐Doped NiCo Alloy Supported on Nickel Foam

AbstractElectrooxidation of biomass‐derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value‐added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high‐efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu−NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu−NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm−2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII−OOH and CoIII−OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu−NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long‐term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass‐derived electrochemical refinery.

Alkaline-Metal Cations Affect Pt Deactivation for the Electrooxidation of Small Organic Molecules by Affecting the Formation of Inactive Pt Oxide.

The activity of Pt for the electro-oxidation of several organic molecules changes with the cation of the electrolyte. It has been proposed that the underlying reason behind that effect is the so-called noncovalent interactions between the hydrated cations and adsorbed OH (OHad). However, there is a lack of spectroscopic evidence for this phenomenon, resulting in an incomplete understanding at the microscopic level of these electrochemical processes. Herein, we explore the electro-oxidation of glycerol (EOG) on platinum (Pt) in LiOH, NaOH and KOH using in situ surface-enhanced infrared absorption spectroscopy in the attenuated total reflectance mode (ATR-SEIRAS) and in situ X-ray absorption spectroscopy (XAS). Our results show that the electrolyte cation influences the rate and potential at which adsorbed CO (COad), a catalytic poison, is formed and oxidized. We attribute this to the cation-dependent stability of oxygenated species on the metallic Pt surface and the different intensities of the electric field at the electrode/electrolyte interface. We also demonstrate that the formation of an inactive Pt oxide layer is indirectly also cation-dependent: the formation of this layer is triggered by the cation-dependent oxidative removal of reaction intermediates (for instance, CO). This phenomenon explains the well-known cation-induced differences in the voltammetric profiles, of not just glycerol, but generally of alcohols and polyols.

Electrooxidation of glycerol to formic acid coupled with Energy-Saving hydrogen production over ruthenium doped Cobalt-Based nanosheet arrays

The utilization of small molecule oxidation reactions as a substitute for the sluggish oxygen evolution reaction (OER) in traditional water electrolysis represents an innovative approach to achieve efficient hydrogen production while concurrently generating value-added chemicals. Herein, we report an energy-saving H2 production system utilizing electrooxidation of glycerol to generate valuable formate. Cobalt–ruthenium oxide nanosheet arrays (CoRuO/CF) and cobalt–ruthenium bimetallic nanoparticles wrapped by nitrogen-doped carbon nanosheet arrays (CoRuCN/CF) were synthesized for glycerol oxidation reaction (GOR) and hydrogen evolution reaction (HER), respectively, using Co-ZIF nanosheets precursor material supported on copper foam (Co-ZIF/CF) as the substrate. Remarkably, the hybrid electrolysis system can achieve a current density of 10 mA cm−2 with only 1.19 V, which is significantly lower than that required by traditional water-splitting systems. This work demonstrates the promising potential of efficiently utilizing biomass energy and achieving a sustainable production process for fine chemical products.

Impact of metal oxides on the selectivity of NiBi/C catalysts for high-value C-3 products in glycerol electrooxidation reaction

Enhancing the catalytic efficiency and specificity of non-noble Nickel-based catalysts for glycerol electro-oxidation reaction (GEOR) is an ongoing challenge. Recently, metal oxides have attracted attention due to their unique physical properties, such as chemical stability at high anodic potentials, presence of oxygen vacancies, which can significantly influence reaction kinetics and pathways.In this study, we explored the impact of metal oxides CeO2, SnO2, and Sb2O3 • SnO2 (ATO) on the electrochemical performance and product selectivity of NiBi/C and Ni/C catalysts in glycerol electrooxidation (GEOR). The Ni/C-X and NiBi/C-X (X= CeO2, SnO2, and ATO) catalysts were synthesized through a sodium borohydride reduction method at room temperature and comprehensively characterized using various physiochemical and electrochemical techniques.Among the composite support catalysts, Ni and NiBi/C-X, Ni/C-ATO exhibited the highest peak current density, reaching 96 mA cm-2 at 1.50 V vs. RHE. To further assess the catalysts' performance, continuous electrolysis, coupled with HPLC analysis, was conducted to determine product selectivity. Notably, NiBi/C-ATO demonstrated remarkable selectivity, achieving 100 % lactate selectivity under mild conditions. These findings contribute valuable insights into optimizing non-noble Nickel-based catalysts for GEOR, particularly highlighting the promising performance of Ni/C-ATO in terms of selectivity towards valuable products. The DFT calculations provided insight into the synergistic interactions for GEOR over Ni-Ni and Bi-Bi nanoparticles.

Ru doping triggering reconstruction of cobalt phosphide for coupling glycerol electrooxidation with seawater electrolysis

Seawater electrolysis is a promising approach for sustainable energy without relying on precious freshwater. However, the large-scale seawater electrolysis is hindered by low catalytic efficiency and severe anode corrosion caused by the harmful chlorine. In contrast to the oxygen evolution reaction (OER) and chlorin ion oxidation reaction (ClOR), glycerol oxidation reaction (GOR) is more thermodynamically and kinetically favorable alternative. Herein, a Ru doping cobalt phosphide (Ru-CoP2) is proposed as a robust bifunctional electrocatalyst for seawater electrolysis and GOR, for the concurrent productions of hydrogen and value-added formate. The in situ and ex situ characterization analyses demonstrated that Ru doping featured in the dynamic reconstruction process from Ru-CoP2 to Ru-CoOOH, accounting for the superior GOR performance. Further coupling GOR with hydrogen evolution was realized by employing Ru-CoP2 as both anode and cathode, requiring only a low voltage of 1.43 V at 100 mA cm−2, which was 250 mV lower than that in alkaline seawater. This work guides the design of bifunctional electrocatalysts for energy-efficient seawater electrolysis coupled with biomass resource upcycling.

Investigation of a novel Defatted Spent Coffee Ground (DSCG)-supported Ni catalyst for fuel cell and supercapacitor applications

With the increase in energy demand, a material that can be used in fuel cell applications has been developed for both energy storage and the use of alternative energy sources to fossil fuels. In this study, a new Defatted Spent Coffee Ground (DSCG)-based electrode material was synthesized for two different application areas. A new electrocatalyst synthesis was carried out by subjecting DSCG to chemical activation and carbonization processes. The glycerol electrooxidation performances of the catalysts synthesized at 10–50 % Ni loading rates were investigated by CV measurements. 30 % Ni-DSCG catalyst exhibited the highest catalytic activity with 3.290 mA/cm2.As a result of the electrochemical measurements, 30 % Ni-DSCG catalyst with the best catalytic performance was used as the supercapacitor electrode material. The electrochemical performances of the produced supercapacitor electrodes were tested at room temperature using galvanostatic charge-discharge (GCD), Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques, and the capacity and stability of the electrodes were calculated as a result of the findings. In the calculations, the energy and power density of the 30 % Ni-DSCG supercapacitor electrode were calculated as 22.897 Wh kg−1, 841.114 W kg−1, respectively. The supercapacitor electrode capacitance was found to be 50.48 F/g.Its cyclic capacity was found to be 90 %. It showed that the DSCG-based synthesized electrocatalyst could be a good option for energy storage technology as EDLC electrode material and fuel cell applications as anode catalyst due to its good conductivity, superior cyclic stability, environmental friendliness and low cost.

Morphology Variation of Ternary PdCuSn Nanocrystalline Assemblies and Their Electrocatalytic Oxidation of Alcohols.

Metal alloys not only increase the composition and spatial distribution of elements but also provide the opportunity to adjust their physicochemical properties. Recently, multimetallic alloy nanocatalysts have attracted great attention in energy applications and the chemical industry. This work presents the production of three ternary PdCuSn nanocrystalline assemblies with similar compositions via a one-step hydrothermal method. The shape variation of assembly units from nanosheets and nanowires to nanoparticles were realized by adjusting the percentage of Sn in metal precursors. Experimental data show that PdCuSn nanowire networks showed the best catalytic activity by virtue of their optimized morphological characteristics and microscopic electronic structure. With electrooxidation of methanol, ethanol, ethylene glycol, and glycerol at 30 °C, PdCuSn nanowire networks demonstrated catalytic activity of 1129, 2111, 2540, and 1445 mA mg-1, respectively. The catalytic activity for alcohol oxidation is attributed to the production of the electronic structure and morphology features that are most suitable. This is achieved by introducing the proper quantities of Cu and Sn components in the first stage of synthesis. This study would help with the construction of high-efficiency nanostructured alloy catalysts by regulating the electronic structure and morphology.

Tuning selectivity toward three-carbon product of glycerol electrooxidation in borate buffer through manipulating borate/glycerol molar ratio

Controlling selective glycerol electrooxidation towards the primary or secondary alcohol group, which enables obtained dihydroxyacetone or glyceraldehyde as the main product, is a challenge for an effective glycerol electrolysis system. In this work, we systematically investigated the protective effect of borate-glycerol complexes toward primary and secondary alcohol group oxidation during the glycerol electrooxidation process on NiOx catalyst in borate buffer (pH 9.2). The Raman spectroscopy and high-performance liquid chromatography results indicated that manipulating the borate/glycerol (B/G) ratio could affect selective oxidation towards primary or secondary alcohol group. Five-member ring complex was more likely to form in the electrolyte with the B/G ratio of 0.1, whereas six-member ring complex became more significant in the electrolyte with the B/G ratio of 1.5. The dominance of five- or six-member ring complex could enhance the favored adsorption of primary or secondary alcohol group, thus generating glyceraldehyde or dihydroxyacetone as the main product, respectively. The results in this study highlight the significance of electrolyte property on glycerol electrocatalysis, which is universally applicable to other transition metal electrocatalysts, enabling the development of a highly selective glycerol electrooxidation towards primary or secondary alcohol system at near-neutral pH level.