Using seawater can reduce the dependence on freshwater resources to generate hydrogen by electrocatalytic water splitting. However, the stability and activity of hydrogen evolution reaction (HER) electrocatalysts are highly influenced by the pH of seawater. In this regard, the development of the practical application of HER depends on the creation of highly active non-noble metal electrocatalysts. Here, we propose a technique to optimize the electrocatalytic activity and stability of MoO₃ by utilizing titanium felt as the substrate. We show an HER overpotential as low as 83 mV at −10 mA cm^–2 in neutral pH conditions. The present results show that electrocatalysts based on earth-abundant metals can perform well in saltwater HER, especially at a near-neutral pH (pH ∼ 7). In a neutral saltwater electrolyte (0.55 M PBS + 0.5 M NaCl), this electrocatalyst showed stable performance for 250 h at a constant current density of −100 mA cm^–2, indicating its promising application in seawater-based hydrogen generation. Compared with noble metals, this electrocatalyst provides a cost-effective option for economic seawater hydrogen generation, promoting the potential of seawater electrolysis.

Nanofibers and nanorods of NiCo- and NiCoFe- oxides and phosphides were synthesized by hydrothermal methods, followed by phosphidation to yield (Ni,Co)P, (Ni,Co)2P, and FeP. The materials were evaluated as electrocatalysts for the oxygen evolution reaction (OER) in water splitting in the presence of a magnetic field in two electrolytes: 1 M KOH and 1 M phosphate buffer saline (PBS) solution. A standard electrochemical cell was equipped with disk magnets directed perpendicular to the electric field. The magnetic field affected the catalyst interface and increased the reaction rate. The best catalyst was found to be NiCoP, and the overpotential (at 10 mA/cm2) was reduced from 330 to 260 mV when a magnetic field of 100 mT was applied and further to 170 mV when a magnetic field of 200 mT was applied. NiCoP has the highest proportion of magnetic domains aligned due to having the highest saturation magnetization (Ms), remanence magnetization (Mr), and the lowest coercivity (Hc). The mixed transition metal phosphide catalysts were found to partly transform into (Ni,Co)3(PO4)2during electrocatalysis; however, they still responded to a change in the magnetic field. The results show that a weak magnetic field can improve the performance of electrocatalysts based on certain transition metals in a neutral pH electrolyte mimicking seawater.

Using seawater to generate green hydrogen through electrolysis is a promising strategy for energy conversion. However, direct seawater splitting to form green hydrogen suffers drawbacks from electrode corrosion due to chlorine and other impurities. Herein, we demonstrate direct electrochemical seawater splitting using a forward osmosis membrane coupled with an electrolysis cell. By using this cell, high activity (270 mV at 10 mA/cm(2)) and decent stability (up to 6 days) are achieved by utilizing RuO2-(Ni,Co)(3)O-4 catalyst in a neutral electrolyte. This system is further studied in various electrolytes under neutral to alkaline conditions. This proof of concept shows that seawater splitting could be coupled with semipermeable membranes, allowing for direct utilization of seawater without pretreatment or purification and evading the challenges posed by impurities.

Subjecting phosphotungstic acid solutions to low pH in combination with introduction of polyvalent cations led to the formation of nanostructured microspheres of approximately 2 μm in size, as shown by scanning electron microscopy, which were almost insoluble and resistant to degradation at neutral and high pH. These microspheres were composed of secondary nanospheres with diameters around 20 nm as revealed by transmission electron microscopy and atomic force microscopy. Investigations of the crystal structure of a potential intermediate of this process, namely, acidic lanthanum phosphotungstate, [La(H₂O)₉](H₃O)₃[PW₁₂O₄₀]₂(H₂O)₁₉, showed a tight network of hydrogen bonding, permitting closer packing of phosphotungstic acid anions, thereby confirming the mechanism of the observed self-assembly process. The new material demonstrated promising electrochemical properties in oxygen evolution reactions with the high stability of the obtained electrode material. 

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.

Electrochemical conversion of glycerol offers a promising route to synthesize value-added glycerol oxidation products (GOPs) from an abundant biomass-based resource. While noble metals provide a low overpotential for the glycerol electrooxidation reaction (GEOR) and high selectivity toward three-carbon (C3) GOPs, their efficiency and cost can be improved by incorporating non-noble metals. Here, we introduce an effective strategy to enhance the performance of Pd nanoparticles for the GEOR by alloying them with Ni. The resulting PdNi nanoparticles show a significant increase in both specific activity (by almost 60%) and mass activity (by almost 35%) during the GEOR at 40 °C. Additionally, they exhibit higher resistance to deactivation compared to pure Pd. Analysis of the GOPs reveals that the addition of Ni into Pd does not compromise the selectivity, with glycerate remaining at around 60% of the product fraction and the other major product being lactate at around 30%. Density functional theory calculations confirm the reaction pathways and the basis for the higher activity of PdNi. This study demonstrates a significant increase in the GEOR catalytic performance while maintaining the selectivity for C3 GOPs, using a more cost-effective nanocatalyst.

Glycerol, being an abundant and cheap by-product of biodiesel production, has emerged as a raw material that can be recycled into value-added compounds. In the present study, Pt nanoparticles of cubic (Pt_CUBE) and dendritic (Pt_DEND) morphologies were investigated as catalysts for the glycerol electrooxidation reaction (GEOR) at 20 °C. To optimise the electrocatalytic performance and GEOR selectivity towards three-carbon (C3) products, namely lactate, glycerate, and tartronate, the effects of morphology, electrolyte composition, and applied potential were studied. At low glycerol concentrations, C–C bond cleavage was more favoured, especially on Pt_DEND. Both Pt_CUBE and Pt_DEND showed high C3 product selectivity up to 91% at 0.67 V vs. RHE, with lactate reaching a maximum selectivity of 68% on Pt_CUBE, which also exhibited the best mass and specific activities compared to Pt_DEND.

Glycerol is a renewable chemical that has become widely available and inexpensive due to the increased production of biodiesel. Noble metal materials have shown to be effective catalysts for the production of hydrogen and value-added products through the electrooxidation of glycerol. In this work we develop three platinum systems with distinct pore mesostructures, e.g., hierarchical pores (HP), cubic pores (CP) and linear pores (LP); all with high electrochemically active surface area (ECSA). The ECSA-normalized GEOR catalytic activity of the systems follows HPC > LPC > CPC > commercial Pt/C. Regarding the oxidation products, we observe glyceric acid as the main three-carbon product (3C), with oxalic acids as the main two-carbon oxidation product. DFT-based theoretical calculations support the glyceraldehyde route going through tartronic acid towards oxalic acid and also help understanding why the dihydroxyacetone (DHA) route is active despite the absence of DHA amongst the observed oxidation products.

Pd octahedral, rhombic dodecahedral, and cubic nanoparticles (Pd_OCTA, Pd_RD, and Pd_CUBE NPs) were synthesized, characterized, and studied as catalysts for the glycerol electrooxidation reaction (GEOR) in a strongly alkaline medium at 20 and 60 °C. The highest mass activity of 0.050 and 0.183 mA/μg_Pd was observed on Pd_OCTA at 20 and 60 °C, respectively, whereas Pd_CUBE exhibited the highest specific activity of 1.49 and 12.84 mA/cm_Pd², respectively. The GEOR products were analyzed by high-performance liquid chromatography (HPLC), and their selectivity and overall glycerol conversion were evaluated at 0.86 V vs RHE. The selectivity toward the three-carbon chain (C3) GEOR products was similar for the different types of catalysts, with Pd_OCTA and Pd_CUBE NPs achieving more than 50% selectivity at 20 °C and more than 60% at 60 °C. Glycerate was the overall dominant product for all catalysts, with a selectivity of up to 42%. The glycerol conversion was found to be highest for Pd_OCTA─21% at 20 °C and 82% at 60 °C, while Pd_RD was the least active and showed less than 3% conversion at 20 °C and 35% at 60 °C. Based on the GEOR product distribution, a reaction mechanism was proposed.

Through glycerol electrooxidation, we demonstrate the viability of using a PdNi catalyst electrodeposited on Ni foam to facilitate industrially relevant rates of hydrogen generation while concurrently providing valuable organic chemicals as glycerol oxidation products. This electrocatalyst, in a solution of 2 M NaOH and 1 M glycerol at 80 °C, enabled current densities above 2000 mA cm^-2 (in a voltammetric sweep) to be obtained in atmospheres of both air and N₂. Repeated potential cycling under an aerated atmosphere to these exceptional current densities indicated a high stability of the catalyst. Through steady state polarisation curves, 1000 mA cm^-2 was reached below an anodic potential of 0.8 V vs RHE. Chronoamperometry showed glycerate and lactate being the major oxidation products, with increased selectivity for lactate at the expense of glycerate in aerated systems. Aerated atmospheres were demonstrated to consistently increase the apparent Faradaic efficiency to >100%, as determined by the concentration of oxidation products in solution. The excellent performance of PdNi/Ni in aerated solutions suggests that O₂ removal from the electrolyte is not needed for an industrial glycerol electrooxidation process, and that combining electrochemical and chemical glycerol oxidation, in the presence of dissolved O₂ presents an important process advantage.