Plasma-Constructed Co2P-Ni2P Heterointerface for Electro­Upcycling of Polyethylene Terephthalate Plastic to Co-Produce Hydrogen and Formate.

Integrating electrochemical upcycling of polyethylene-terephthalate (PET) and the hydrogen evolution reaction (HER) is an energy-saving approach for electrolytic hydrogen (H2) production, along with the coproduction of formate. Herein, a novel and rapid strategy of cold plasma phosphating is employed to synthesize Co2P-Ni2P heterointerface decorated on carbon cloth (Co2P-Ni2P/CC) to catalyze H2 generation and reform PET. Notably, the obtained Co2P-Ni2P/CC exhibits eminent ethylene glycol oxidation reaction (EGOR) and HER activities, effectuating low potentials of merely 1.300 and -0.112 V versus RHE at 100 mA cm-2 for the EGOR and HER, respectively, also attaining an ultralow cell bias of 1.300 V at 10 mA cm-2 for EG oxidation assisted-water splitting. DFT and characterization results validate that the as-formed built-in electric fields in the Co2P-Ni2P heterointerface can accelerate electrons transfer and deepen structural self-reconstruction, thereby boosting effectively water dissociation and ethylene glycol (EG) dehydrogenation. Impressively, coupling HER with PET-derived EG-to-formate in a flow-cell electrolyzer assembled with Co2P-Ni2P/CC pair achieves an intriguing formate Faradaic efficiency of 90.6% and an extraordinary stable operation of over 70 h at 100 mA cm-2. The work exemplifies a facile and effective strategy for synthesizing metal phosphides electrocatalysts with extraordinary performance toward H2 generation of water splitting and recycling of PET.

Solvothermal synthesis of PdCu nanorings with high catalytic performance for alcohol electrooxidation.

Two-dimensional (2D) Pd-based nanostructures with a high active surface area and a large number of active sites are commonly used in alcohol oxidation research, whereas the less explored ring structure made of nanosheets with large pores is of interest. In this study, we detail the fabrication of PdCu nanorings (NRs) featuring hollow interiors and low coordinated sites using a straightforward solvothermal approach. Due to increased exposure of active sites and the synergistic effects of bimetallics, the PdCu NRs exhibited superior catalytic performance in both the ethanol oxidation reaction (EOR) and the ethylene glycol oxidation reaction (EGOR). The mass activities of PdCu NRs for EOR and EGOR were measured at 7.05 A/mg and 8.12 A/mg, respectively, surpassing those of commercial Pd/C. Furthermore, the PdCu NRs demonstrated enhanced catalytic stability, maintaining higher mass activity levels compared to other catalysts during stability testing. This research offers valuable insights for the development of efficient catalysts for alcohol oxidation.

Facilitating Formate Selectivity via Optimizing eg* Band Broadening in NiMn Hydroxides for Ethylene Glycol Electro-Oxidation.

Ethylene glycol electro-oxidation reaction (EGOR) on nickel-based hydroxides (Ni(OH)2) represents a promising strategy for generating value-added chemicals, i.e. formate and glycolate, and coupling water-electrolytic hydrogen production. The high product selectivity was one of the most significant area of polyols electro-oxidation process. Yet, developing Ni(OH)2-based EGOR electrocatalyst with highly selective product remains a challenge due to the unclear cognition about the EGOR mechanism. Herein, Mn-doped Ni(OH)2 catalysts were utilized to investigate the EGOR mechanism. Experimental and calculation results reveal that the electronic states of eg* band play an important role in the catalytic performance and the product selectivity for EGOR. Broadening the eg* band could effectively enhance the adsorption capacity of glyoxal intermediates. On the other hand, this enhanced adsorption could lead to reduced side reactions associated with glycolate formation, simultaneously promoting the cleavage of C-C bonds. Consequently, the selectivity for formate was notably augmented by these enhancements. This work offers new insights into the regulation of catalyst electronic states for improving polyol electrocatalytic activity and product selectivity.

Alkali Etching of Porous PdCoZn Nanosheets for Boosting C-C Bond Cleavage of Ethylene Glycol Oxidation.

Pd-based electrocatalysts are the most effective catalysts for ethylene glycol oxidation reaction (EGOR), while the disadvantages of poor stability, low resistance to neutrophilic, and low catalytic activity seriously hamper the development of direct ethylene glycol fuel cells (DEGFCs). In this work, defect-riched PdCoZn nanosheets (D-PdCoZn NSs) with ultrathin 2D NSs and porous structures are fabricated through the solvothermal and alkali etching processes. Benefiting from the presence of defects and ultrathin 2D structures, D-PdCoZn NSs demonstrate excellent electrocatalytic activity and good durability against EGOR in alkaline media. The mass activity and specific activity of D-PdCoZn NSs for EGOR are 9.5 A mg-1 and 15.7 mA cm-2 , respectively, which are higher than that of PdCoZn NSs, PdCo NSs, and Pd black. The D-PdCoZn NSs still maintain satisfactory mass activity after long-term durability tests. Meanwhile, in situ IR spectroscopy demonstrates that the presence of defects attenuated the adsorption of intermediates, which improves the selectivity of the C1 pathway with excellent anti-CO poisoning performance. This work not only provides an effective synthetic strategy for the preparation of Pd-based nanomaterials with defective structures but also indicates significant guidance for optimum C1 pathway selectivity of ethylene glycol and other challenging chemical transformations.

One-pot synthesis of 3D surface-wrinkled PdAu nanospheres for robust alcohols electrocatalysis.

Three dimensional (3D) noble-metal nanomaterials with special surface structures have been regarded as high-performance catalysts for alcohol oxidation on account of their superior thermal stability, electrical conductivity and large specific surface area. Although extensive efforts have been devoted to the preparation of 3D Pd-based catalysts with superior activity and stability, designing a simple, effective and eco-friendly method remains a challenge. Herein, we developed a facile one-step coreduction strategy to synthesize a series of 3D surface-wrinkled PdAu nanospheres (NSs) with tunable Pd/Au atomic ratios and found a universal method to prepare surface-wrinkled PdM (M = Au, Pt, Cu and Pb) NSs. Benefiting from the function of the surfactant cetyltrimethylammonium chloride (CTAC), the synthesized PdAu NSs with different composition possess abundant surface wrinkles, which is beneficial for exposing more electroactive centers. Attributed to the unique geometric morphology and optimized atomic ratio, the PdAu-2 NSs exhibited an optimal mass activity (MA) of 8103 mA mg-1 and 5113 mA mg-1 for the ethylene glycol oxidation reaction (EGOR) and ethanol oxidation reaction (EOR), which was 6.1 and 4.1 times that of commercial Pd/C, respectively. Moreover, the PdAu-2 NSs exhibited superb stability after long-term current-time (i-t) and cyclic voltammetry (CV) tests of the EGOR and EOR. This work not only provides new avenues to engineer PdAu NSs with enhanced electrocatalytic performance but also offers guidance for extending to more 3D PdM (M = other metals) NSs with novel morphology applied to fuel cell fields.

Pt nanoclusters embedded Fe-based metal-organic framework as a dual-functional electrocatalyst for hydrogen evolution and alcohols oxidation.

Design and construction of high-efficiency and durable dual-functional electrocatalyst for clean energy electrocatalytic reaction is urgently desirable for mitigating the energy shortage and environmental deterioration issues. Herein, we prepared Pt nanoclusters with exposed (111) face plane embedded Fe-based metal-organic frameworks (Fe-MOF, MIL-100(Fe)) catalyst for electrocatalytic hydrogen evolution reaction (HER) and ethylene glycol oxidation reaction (EGOR). It is noted that the available oxygen sites on the surface of MIL-100(Fe) would form Pt-O interaction with Pt nanoclusters to acquire strong interfacial interaction, which endows Pt/MIL-100(Fe) electrocatalyst effective electron transfer, increasing catalytic active sites, accelerating proton-electron coupling, and improving conductivity. Benefitting from the desirable metal-supports interaction and derive merits for catalysis, the high electrocatalytic activity and durability for HER and EGOR were achieved as expected. Impressively, superior HER performance with higher current density, lower overpotential (46/29 mV in acidic/alkaline electrolyte) and smaller Tafel slope (19.7/37.8 mV dec-1 in acidic/alkaline electrolyte) were acquired compared to commercial Pt/C. Moreover, Pt/MIL-100(Fe) electrode exhibits a rather high mass activity of 11826 mA mg-1Pt and long-term stability for EGOR. The present investigation demonstrates the promise of active metal/MOF combination for the interfacial strategy and rational design of dual-functional electrocatalyst, which has potential applications for future electrocatalysis field.

Extraordinary p-d Hybridization Interaction in Heterostructural Pd-PdSe Nanosheets Boosts C-C Bond Cleavage of Ethylene Glycol Electrooxidation.

Advanced electrocatalysts for complete oxidation of ethylene glycol (EG) in direct EG fuel cells are strongly desired owing to the higher energy efficiency. Herein, Pd-PdSe heterostructural nanosheets (Pd-PdSe HNSs) have been successfully fabricated via a one-step approach. These Pd-PdSe HNSs feature unique electronic and geometrical structures, in which unconventional p-d hybridization interactions and tensile strain effect co-exist. Compared with commercial Pd/C and Pd NSs catalysts, Pd-PdSe HNSs display 5.5 (6.6) and 2.5 (2.6) fold enhancement of specific (mass) activity for the EG oxidation reaction (EGOR). Especially, the optimum C1 pathway selectivity of Pd-PdSe HNSs reaches 44.3 %, illustrating the superior C-C bond cleavage ability. Electrochemical in situ FTIR spectroscopy and theoretical calculations demonstrate that the extraordinary p-d hybridization interaction and tensile strain effect could effectively reduce the activation energy of C-C bond breaking and accelerate CO* oxidation, boosting the complete oxidation of EG and improving the catalytic performance.

One-pot synthesis of rugged PdRu nanosheets as the efficient catalysts for polyalcohol electrooxidation.

Recently, intensive attention has been attracted to the two-dimensional metal nanosheets, owing to their excellent electrocatalytic performance for direct alcohol fuel cells (DAFCs). Herein, PdRu nanosheets have been synthesized successfully by a facile one-pot method. The rugged nanosheet structure provided plentiful surface active sites to enhance the electrocatalytic activity. Moreover, benefiting from the synergistic effect and improved electronic structure, PdRu NSs exhibited splendid electrocatalytic performance in ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR). Specifically, the mass activity of PdRu NSs was 1.72 and 3.69 times over those of Pd NSs and Pd/C catalysts in EGOR. Moreover, PdRu NSs displayed the largest mass activity in GOR, 1.48 and 2.47 times as large as Pd NSs and Pd/C catalysts. The results of stability tests demonstrated that the durability of PdRu NSs was the highest among the obtained catalysts. This work plays a directive role on the in-depth engineering on Pd-based catalysts with nanosheet architectures.

Highly Active Hollow RhCu Nanoboxes toward Ethylene Glycol Electrooxidation.

The efficient electrocatalysts toward the ethylene glycol oxidation reaction (EGOR) are highly desirable for direct ethylene glycol fuel cells because of the sluggish kinetics of anodic EGOR. Herein, porous RhCu nanoboxes are successfully prepared through facile galvanic replacement reaction and succedent sodium borohydride reduction strategy. Benefiting from hierarchical pore structure, RhCu nanoboxes display excellent electrocatalytic performance toward the EGOR in alkaline medium with a mass activity of 775.1 A gRh -1 , which is 2.8 times as large as that of commercial Rh nanocrystals. Moreover, the long-term stability of RhCu nanoboxes is better than that of commercial Rh nanocrystals. Furthermore, the theoretical calculations demonstrate that RhCu nanoboxes possess lower adsorption energy of CO and lower reaction barrier (0.27 eV) for the COads oxidation with aid of the adsorbed OHads species, resulting in the outstanding electrocatalytic performance toward the EGOR. This work provides a meaningful reference for developing highly effective electrocatalysts toward the EGOR.

C2 Alcohol Oxidation Boosted by Trimetallic PtPbBi Hexagonal Nanoplates.

The exploration of ternary Pt-based catalysts represents a new trend for the application of electrocatalysts in fuel cells. In the present study, intermetallic PtPbBi hexagonal nanoplates (HNPs) with a hexagonal close-packed structure have been successfully synthesized via a facile solvothermal synthesis approach. The optimized PtPbBi HNPs exhibited excellent mass activity in the ethanol oxidation reaction (8870 mA mg-1Pt) in an alkaline ethanol solution, which is 12.7 times higher than that of JM Pt/C. Meanwhile, the mass activity of PtPbBi HNPs in an ethylene glycol solution (10,225 mA mg-1Pt) is 1.85 times higher than that of JM Pt/C. In particular, its catalytic activity is better than that of most reported Pt-based catalysts. In addition, the optimized PtPbBi HNPs also show a better operational durability than commercial Pt/C. For the ethylene glycol oxidation reaction, a mass activity of 42.7% was retained even after a chronoamperometric test for 3600 s, which is rare among the reported Pt-based catalysts. By combining X-ray photoelectron spectroscopy and electrochemical characterization, we reveal the electron transfer between Pt, Pb, and Bi; this would lead to weakened CO adsorption and enhanced OH adsorption, thereby promoting the removal of toxic intermediates and ensuring that PtPbBi HNP samples have high activity and excellent stability. This work can inspire the design and synthesis of Pt-based nanocatalysts.

Segmentation and Re-encapsulation of Porous PtCu Nanoparticles by Generated Carbon Shell for Enhanced Ethylene Glycol Oxidation and Oxygen-Reduction Reaction.

Hierarchical porous carbon-encapsulated ultrasmall PtCu (UsPtCu@C) nanoparticles (NPs) were constructed based on segmentation and re-encapsulation of porous PtCu NPs by using glucose as a green biomass carbon source. The synergistic electronic effect from the bimetallic elements can enhance the catalytic activity by adjusting the surface electronic structure of Pt. Most importantly, the generated porous carbon shell provided a large contact surface area, excellent electrical conductivity, and structural stability, and the ultrasmall PtCu NPs exhibited an increased electrochemical performance compared with their PtCu matrix because of the exposure of more catalytically active centers. This synergistic relationship between the components resulted in enhanced catalytic activity and better stability of the obtained UsPtCu@C for ethylene glycol oxidation reaction and the oxygen-reduction reaction in alkaline electrolyte, which was higher than the PtCu NPs and commercial Pt/C (20 wt % Pt on Vulcan XC-72). The electrochemically active surface areas of the UsPtCu@C, PtCu NPs, and commercial Pt/C were calculated to be approximately 230.2, 32.8, and 64.0 m2/gPt, respectively; the mass activity of the UsPtCu@C for the ethylene glycol oxidation reaction was 8.5 A/mgPt, which was 14.2 and 8.5 times that of PtCu NPs and commercial Pt/C, respectively. The specific activity of UsPtCu@C was 3.7 mA/cmpt2, which was 2.1 and 2.3 times that of PtCu NPs and commercial Pt/C, respectively. The onset potential (Eon-set) of UsPtCu@C for the oxygen-reduction reaction was 0.96 V (vs reversible hydrogen electrode, RHE), which was 110 and 60 mV higher than PtCu and commercial Pt/C, respectively. The half-wave potentials (E1/2) of UsPtCu@C, PtCu, and Pt/C were 0.88, 0.56, and 0.82 V (vs RHE), respectively, which indicated that the UsPtCu@C catalyst had an excellent bifunctional electrocatalytic activity.

Trimetallic PtRhCo petal-assembled alloyed nanoflowers as efficient and stable bifunctional electrocatalyst for ethylene glycol oxidation and hydrogen evolution reactions.

Controllable synthesis of multimetal nanocrystals with hierarchical structures and tunable compositions are feasible to steeply improve the catalytic properties in fuel cells. Herein, trimetallic PtRhCo petal-assembled alloyed nanoflowers (PtRhCo PAANFs) were fabricated via a one-pot solvothermal method, which showed remarkable enlargement in specific activity and mass activity over PtRh0.25Co nanodentrites (NDs), PtRh1.5Co NDs, PtCo NDs and commercial Pt/C catalysts for ethylene glycol oxidation in 0.5 M KOH solution. The as-developed catalyst exhibited dramatically better CO tolerance and recoverability, coupling with the superior activity and durability for hydrogen evolution reaction (HER) in the alkaline electrolyte. This work demonstrates the significance of Rh in the alloy for improving the stability. This work offers a promising strategy for preparation of advanced trimetallic electrocatalysts for energy conversion applications.

Porous dendritic PtRuPd nanospheres with enhanced catalytic activity and durability for ethylene glycol oxidation and oxygen reduction reactions.

Developing highly active and durable catalyst is of pivotal importance in fuel cells, owing to excessive consumption of fossil fuels. Herein, porous dendritic PtRuPd nanospheres (PtRuPd NSs) were synthesized by a facile hexadecylpyridinium chloride (HDPC)-mediated one-pot aqueous method with ascorbic acid (AA) as the reducing agent. The as-obtained PtRuPd NSs displayed high-efficient catalytic activity and durability for ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR). It exhibited enlarged mass activity (MA, 1.368 A mg-1) compared to commercial Pt/C (1.100 A mg-1) for EGOR. Besides, the onset potential (Eonset, 0.930 V) and half-wave potential (E1/2, 0.852 V) of PtRuPd NSs were more positive relative to homemade PtPd NSs (0.905 and 0.840 V), PdRu NSs (0.895 and 0.839 V), and commercial Pt/C (0.910 and 0.822 V) toward ORR. This work provides some valuable guidelines for producing novel trimetallic nanocatalysts in fuel cells.

Ultrathin PdFePb nanowires: One-pot aqueous synthesis and efficient electrocatalysis for polyhydric alcohol oxidation reaction.

Synthesis of high-efficiency catalysts for alcohol oxidation reaction caused great interest in direct alcohol fuel cells (DAFCs). Ultrathin PdFePb nanowires (NWs) with an average diameter of 2.3 nm were synthesized by a simple and fast one-pot aqueous synthesis, using octylphenoxypolyethoxyethanol (NP-40) as the structure-directing agent. The as-prepared PdFePb NWs displayed an increscent electrochemically active surface area (ECSA, 121.18 m2 g-1 Pd). For ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR), PdFePb NWs exhibited much higher activity and superior stability, outperforming those of homemade PdFe NWs, PdPb NWs, commercial Pd black and Pd/C (20 wt%). These results reveal dramatically high catalytic activity and durability of ultrathin PdFePb NWs in enhancing polyols electrooxidation.

Highly efficient ethylene glycol electrocatalytic oxidation based on bimetallic PtNi on 2D molybdenum disulfide/reduced graphene oxide nanosheets.

In this paper, a two-dimensional (2D) hybrid material of molybdenum disulfide (MoS2)/reduced graphene oxide (RGO) is facilely synthesized and used as an ideal support for the deposition of Pt nanoparticles. The as-prepared Pt/MoS2/RGO composites are further worked as electrocatalysts towards ethylene glycol oxidation reaction (EGOR). In addition, when alloying with Ni, the composite shows obvious enhancement in electrocatalytic performance for EGOR. Specifically, the optimized molar ratio of Pt to Ni is 3:1, namely Pt3Ni/MoS2/RGO performs the strongest current density of 2062 mA mg-1Pt, which is 11.1, 5.80 and 2.40 times higher than those of Pt, Pt3Ni and Pt/MoS2/RGO electrodes, respectively. The systematically electrochemical measurements indicate that the largely promoted electrocatalytic performances of Pt3Ni/MoS2/RGO are mainly attributed to the synergistic effect of Ni and Pt, and 2D sheets of MoS2/RGO. This excellent performance indicates that the reported electrocatalytic material could be an efficient catalyst for the application in direct ethylene glycol fuel cell and beyond.

Uric acid supported one-pot solvothermal fabrication of rhombic-like Pt35Cu65 hollow nanocages for highly efficient and stable electrocatalysis.

High activity and good durability of electrocatalysts are of significance in practical applications of fuel cells. Among them, multi-component metallic hollow nanocages/nanoframes show great potential as advanced catalysts because of their highly open structures, large surface area and good stability. Herein, we report a general uric acid-mediated solvothermal method for shape-controlled synthesis of rhombic-like Pt35Cu65 hollow nanocages (HNCs) with uric acid as co-reductant and co-structure-directing agent. Uric acid and cetyltrimethylammonium chloride (CTAC) played important roles in the hollow cages. The specific architectures showed remarkably enhanced catalytic properties towards glycerol oxidation reaction (GOR), ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR) with the enhanced specific activity, outperforming commercial Pt/C (20 wt%). This work provides a new avenue for rational design of novel bimetallic nanocatalysts with enhanced characters in energy storage and conversion.

Facile solvothermal fabrication of polypyrrole sheets supported dendritic platinum-cobalt nanoclusters for highly efficient oxygen reduction and ethylene glycol oxidation.

Herein, uniform dendritic PtCo nanoclusters supported on sheet-like polypyrrole (PtCo NCs/PPy) were prepared by a facile one-pot solvothermal method. Cetyltrimethylammonium chloride (CTAC) and pyrrole worked as the capping agent and reductant, respectively, and pyrrole was in-situ polymerized to form PPy sheets under solvothermal conditions. The dendritic PtCo NCs/PPy had the enlarged electrochemically active surface area (EASA, 30.95 m2g-1), and showed the superior catalytic performance and durability towards oxygen reduction reaction (ORR) and ethylene glycol oxidation reaction (EGOR) in comparison with Pt1Co3 nanoparticles (NPs), Pt3Co1 NPs and commercial Pt/C catalysts. This work displays a new strategy for rational design and synthesis of advanced functional nanocomposites as electrocatalysts in fuel cells.

Platinum69-cobalt31 alloyed nanosheet nanoassemblies as advanced bifunctional electrocatalysts for boosting ethylene glycol oxidation and oxygen reduction.

Pt-based bimetallic nanocrystals are feasible to dramatically improve the catalytic performances in fuel cells via morphology- and composition-engineering. Herein, bimetallic platinum69-cobalt31 nanosheet nanoassemblies (Pt69Co31 NSNSs) were facilely synthesized through a one-pot co-reduction solvothermal strategy in oleylamine (OAm), using cetyltrimethylammonium chloride (CTAC) and allantoin as the directing agents. The current synthesis highly depended on the critical concentrations of Pt and Co precursors, the combined use of allantoin to OAm as the co-reductant, and the use of proper allantoin concentration. The obtained nanocatalyst exhibited largely enhanced electrocatalytic activity and durable ability towards ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR) relative to home-made Pt85Co15 nanoparticles (NPs), Pt19Co81 NPs and Pt black catalysts due to its much larger electrochemically active surface area than the contrasts.

Dendrite-like PtAg alloyed nanocrystals: Highly active and durable advanced electrocatalysts for oxygen reduction and ethylene glycol oxidation reactions.

In this work, well-defined dendrite-like PtAg alloyed nanocrystals were prepared by a facile one-pot l-hydroxyproline-assisted successive coreduction approach on a large scale, where no any template or seed involved. l-Hydroxyproline was employed as a green structuring director. The formation mechanism of the alloyed dendritic nanocrystals was investigated in details. The as-prepared frameworks exhibited boosted electrocatalytic activity, improved stability and enhanced tolerance toward oxygen reduction reaction (ORR) and ethylene glycol oxidation reaction (EGOR) in alkaline media in contrast with commercial Pt black catalyst. The developed method provides novel strategy for preparing other shape-controlled nanocatalysts with superior catalytic activity and durability.