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In the present study, various mesoporous TixW1-xO2 (x = 0.5; 0.6; 0.7; 0.8) supports were fabricated via a facile solvothermal approach and explored the effect of doping tungsten concentration on electrochemical properties of TixW1-xO2-supported Pt electrocatalysts toward ethanol electrochemical reaction. Interestingly, the incorporation of tungsten into TiO2 lattices with the doping tungsten amounts (20 and 30 at %) resulted in boosting both the surface area and electrical conductivity, however, a reverse trend was observed when increasing the doped tungsten content more than 40 at %. Additionally, the relatively well-distributed Pt nanoparticles with the small particle size (ca. 3 nm) anchored on supports were achieved using a microwave-assisted polyol route. Electrochemical results indicated that various TixW1-xO2-supported Pt catalysts exhibited the catalytic performance greater than that of the commercial carbon-supported Pt (E-TEK) catalyst for ethanol electro-oxidation reaction (EOR). For as-obtained electrocatalysts, the Ti0.7W0.3O2-supported Pt catalyst showed the highest mass activity (~260.23 mA/mgPt) and greatest If/Ib ratio (~1.34), which ~2.0-fold and ~1.57-time higher than that of carbon-supported Pt (E-TEK) catalyst (~130.62 mA/mgPt for mass activity and ~0.85 for If/Ib ratio, respectively). After 5000 cycling tests, the mass activity loss of TixW1-xO2-supported Pt catalysts was around twice lower than that of the commercial Pt/C (E-TEK) catalysts, suggesting that the TixW1-xO2-supported Pt catalysts exhibited the superior stability toward ethanol electrochemical oxidation. The outstanding electrochemical activity and stability of TixW1-xO2-supported Pt electrocatalysts were owing to the synergetic effect between Pt nanocatalyst and non-carbon TixW1-xO2 supports as well as superior natural durability of TiO2-based materials.

In this work, an anatase Ti0.7W0.3O2-supported Pt3Ru nanoparticles (NPs) were fabricated by combining the advantages of the non-carbon Ti0.7W0.3O2 nanosupport and the synergistic effect of the bimetallic Pt3Ru nanoalloy that was investigated as electrocatalyst toward alcohol electrochemical oxidation. The bimetallic Pt3Ru nanoparticles with ~3 nm in diameter were relatively well-dispersed on the surface of the anatase Ti0.7W0.3O2 nanosupport via a surfactant-free microwave-assisted polyol route that, which was attributable to the good dispersibility of ethylene glycol and the rapid, uniformity of the microwave heating. For methanol and ethanol electrochemical oxidation, the as-obtained Pt3Ru (NPs)/Ti0.7W0.3O2 electrocatalyst exhibited the low onset potential (~0.10 V vs. NHE for MOR and ~0.35 V vs. NHE for EOR) and high mass activity (~350.84 mA mgPt−1 for MOR and ~274.59 mA mgPt−1 for EOR) compared to the commercial Pt (NPs)/C (E-TEK) electrocatalyst. Additionally, the CO-stripping and CA results indicated the remarkably enhanced CO-tolerance of the Pt3Ru (NPs)/Ti0.7W0.3O2 catalyst. After the 5000-cycle accelerated durability test (ADT) in acidic ethanol media, the bimetallic Pt3Ru (NPs)/Ti0.7W0.3O2 catalyst only showed the mass activity loss of 19.11% of its initial mass activity, compared with the severe deterioration of 44.04% of the commercial Pt (NPs)/C (E-TEK) catalyst. The outstanding results could be interpreted due to the bifunctional mechanism of the Pt3Ru nanoalloys combining with the synergistic effect between the bimetallic nanoalloy and the mesoporous Ti0.7W0.3O2 nanosupport as well as the superior anti-corrosion of the TiO2-based nanosupport under acidic and oxidative environments.

This work focuses on the formation of Ir3+ dopants in host TiO2 matrix to decrease the bandgap energy and a built-in electric field at the interface between Iro and TiO2. X-ray diffraction (XRD) re...

Direct methanol fuel cells (DMFCs) have attracted considerable scientific interest because of their ease of operation and implementation; however, poor electrocatalytic activity and durability are the main hindrances for their commercial feasibility. Moreover, the deactivation of active Pt sites, due to the coverage of CO-like species during the electrochemical oxidation reaction, significantly degrades the electrochemical surface area (ECSA). In the present work, stable Pt-supported tin-modified indium oxide (ITO) was synthesized as a promising electrocatalyst towards the methanol oxidation reaction (MOR) in DMFCs. It was found that 20 wt% Pt/ITO yielded much higher current density (∼0.71 mA/cm2) than the state-of-the-art carbon-supported Pt (E-TEK) electrocatalyst. Furthermore, the If/Ib ratio, which featured the CO tolerance of the electrocatalyst, of 20 wt% Pt/ITO was found to be ∼1.42, which is ∼1.5-fold higher than that of 20 wt% Pt/C (E-TEK). Chronoamperometry results indicated that 20 wt% Pt/ITO manifested much higher stability than 20 wt% Pt/C (E-TEK).

High cost and poor durability of Pt-based electrocatalysts are the main challenges for future commercialization of direct ethanol fuel cells (DEFCs). In the present work, a stable and effective Pt/Ti0.8W0.2O2 electrocatalyst toward ethanol electrooxidation reactions (EORs) was prepared by utilizing the attributes of noncarbon catalyst supports and low Pt loading. The 18.5 wt % Pt/Ti0.8W0.2O2 electrocatalyst was successfully fabricated through a simple and rapid microwave-assisted polyol route (ethylene glycol was used as a reducing agent). In comparison with a conventional 20 wt % Pt/C electrocatalyst, the as-prepared 18.5 wt % Pt/Ti0.8W0.2O2 electrocatalyst resulted in much lower onset potential, higher If/Ib value, and superior stability toward EOR, which can be ascribed to the synergistic effect between Pt nanocatalyst and the Ti0.8W0.2O2 catalyst support. Therefore, these findings imply that 18.5 wt % Pt/Ti0.8W0.2O2 is a promising anodic electrocatalyst and possesses the ability to replace Pt/C electrocatalysts in the future.

To overcome the disadvantages of commercial carbonaceous catalysts in direct methanol fuel cells (DMFCs), novel Pt/Ti1–xIrxO2 catalysts are fabricated in this study. Simultaneously, the influence of the Ir composition in the support on the electrocatalytic activities and physicochemical properties of Pt/Ti1–xIrxO2 catalysts is also evaluated. Ti1–xIrxO2 materials with the tunable Ir composition (x = 0.1, 0.2, 0.3) synthesized via a simple and green hydrothermal route exhibited much higher electrical conductivity and surface area than the undoped TiO2. Furthermore, the well-distributed Pt nanoparticles (NPs) with small sizes (∼3 nm) over supports were obtained by using a modified chemical reduction route. Electrochemical results revealed that a series of 20 wt. % Pt/Ti1–xIrxO2 catalysts exhibited superior durability and electrochemical activity toward the methanol oxidation reaction to the commercial 20 wt. % Pt/C (E-TEK) catalyst. According to these results, Ti1–xIrxO2 materials seem to be very promising as a stable catalyst support in the harsh medium of DMFCs.

The novel nanostructured Ti0.9Ir0.1O2 acting as a potential catalyst support for Pt in fuel cell applications was easily synthesized by means of a facile and simple low-temperature hydrothermal process without using any surfactants and further heat treatment. Interestingly, even in low iridium doping concentration, the Ti0.9Ir0.1O2 support possessed the high electronic conductivity of 0.016 S/cm, which was ∼105 times as high as pure TiO2 (4.15 × 10−7 S/cm), suggesting the efficient doping of iridium into TiO2 lattice. Furthermore, the modified chemical reduction route utilized to prepare the 20 wt % Pt/Ti0.9Ir0.1O2 electrocatalyst exhibited the good anchoring and uniform distribution of Pt nanoparticles (NPs) (∼3 nm) over Ti0.9Ir0.1O2 surface and thus eventually resulted in the high electrochemical surface area (∼85.08 m2/gPt) compared to that of the commercial 20 wt % Pt/C (E-TEK) catalyst (∼69.21 m2/gPt). The cyclic voltammetry results in the methanol media revealed that the 20 wt % Pt/Ti0.9Ir0.1O2 displayed the superior electrocatalytic activity compared to the 20 wt % Pt/C (E-TEK) catalyst towards the methanol electro-oxidation. For instance, the 20 wt % Pt/Ti0.9Ir0.1O2 catalyst possessed the higher oxidation current density (∼28.8 mA/cm2), the lower onset potential (∼0.12 V) and the higher If/Ib ratio in comparison with the commercial 20 wt % Pt/C (E-TEK) catalysts. It is worth noting that the chronoamperometry results also indicated that the 20 wt % Pt/Ti0.9Ir0.1O2 exhibited higher durability than the commercial 20 wt % Pt/C (E-TEK) catalyst. Beside introducing novel Ti0.9Ir0.1O2 material, these results also offer a pathway of exploring the low dopants content of TixIr1-xO2 material to serve as a good catalyst support for many fuel cell applications.

Late transition metal doped TiO2 has been exploited for generating efficient catalyst support by enhancing electrical conductivity and modifying properties of TiO2. The Ti0·7Ir0·3O2 nanorod (NRs), a novel catalyst support for Pt nanoparticles, was prepared for the first time via single-step hydrothermal process at low temperature using IrCl3·3H2O and TiCl4 as starting materials. We found that the Ti0·7Ir0·3O2 NRs with 70–80 nm in length and 25–30 nm in width is successful prepared at 210 °C for 12 h without utilizing surfactants or stabilizers. In addition, the Ti0·7Ir0·3O2 NRs was presented principally as a single-phase solid with the TiO2 is in the rutile form with high crystallinity without using further treatment after synthesis. More importantly, we found that the Ti0·7Ir0·3O2 NRs possesses high electrical conductivity (0.028 S cm−1) dealing the intrinsically non-conducted drawback of TiO2. The Pt nanoparticles were then deposited on the support of Ti0·7Ir0·3O2 NRs via chemical reduction method. The properties of 20 wt % Pt/Ti0·7Ir0·3O2 NRs electrocatalyst were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), the cyclic voltammetry (CV). The uniformly distributed small Pt nanoparticles (3–4 nm diameter) were well adhered to the Ti0·7Ir0·3O2 NRs. The electrochemically active surface area (ECSA) of 20 wt % Pt/Ti0·7Ir0·3O2 NRs was higher than that of the commercial 20 wt % Pt/C (E-TEK) due to the small size and good dispersion of Pt nanoparticles on the surface of Ti0·7Ir0·3O2 NRs. Moreover, the ECSA value of the Pt/Ti0·7Ir0·3O2 NRs retained up to 88% after 2000 cycles of cyclic voltammetry, suggesting the high stability of catalyst resulted from strong metal support interaction (SMSI) of Titania-based materials with the noble metals. More importantly, the onset potential of Pt/Ti0·7Ir0·3O2 NRs catalyst towards oxygen reduction reaction is more positive (∼80 mV) compared to commercial Pt/C, indicating the high catalytic activity of the Pt/Ti0·7Ir0·3O2 NRs catalyst. The results of this research suggested that novel Ti0·7Ir0·3O2 NRs could be applied as promising robust non-carbon support for Pt. This research also creates a preliminary step for investigating systematically promising Iridium doped Titania materials.

The degradation of Pt-based catalysts is considered as the main barrier to the commercialization of fuel cells. M-doped TiO2 (M is a transition metal) has been investigated to improve the stability of electrocatalysts. Recently, W-doped TiO2 materials have been found as a good catalyst support for the photocatalyst applications but their application in Proton-exchange membrane fuel cell application has rarely been reported. In addition, the agglomeration of nanoparticles, which are synthesized from the organic precursor, has been reported. Here, we report Ti0.7W0.3O2 nanoparticles prepared via a one-step solvothermal method with inorganic precursors without using surfactants or stabilizers for restricting nanoparticle agglomeration. The properties of the material were measured by XRD, TEM, BET, and electronic conductivity. The mean particle size of ∼5 nm, the high specific surface area of 126.471 m2/g and a moderate electronic conductivity of 0.014 S/cm were obtained for the sample prepared at 220 °C for 4 h. It was observed that using inorganic precursors to prevent particle agglomeration is more advantageous compared to organic precursors as mentioned in previous reports.

Non-carbon materials are considered as the promising candidates for carbon-based catalyst support to increase the durability of proton exchange membrane fuel cells (PEMFCs). Due to the high stability and good electrical conductivity of TiO2, M-doped TiO2 (M is transition metals: Mo, Ru, V, W) is an emerging candidate for Pt nanoparticles support on the cathode side of PEMFCs. In this research, the synthesis mechanism of Ti0.7Ir0.3O2 nanostructure by the one-step hydrothermal method at low temperature was studied. We found that by only controlling the pH of the precursor solution, Ti0.7Ir0.3O2 can be synthesized with different morphology and phase selection without any formation of mixed oxides. In particular, Ti0.7Ir0.3O2 nanostructure synthesized at pH = 0 exhibited concomitant anatase, brookite, and rutile phases. The spherical particles of diameter 20-40 nm, cubic particles of 30-50 nm in side-length and rod-like particles with 70 nm in length and 20 nm in diameter represented the anatase, brookite, and rutile phases respectively. At a pH value of 1 or 2, the majority of spherical nanoparticles were homogeneous at 15-20 nm in diameter. It was observed that the electronic conductivity of novel Ti0.7Ir0.3O2 nanostructure was significantly higher than that of the undoped TiO2. Thus the promising properties of this new nanostructure open a new path to the much-needed fuel cell applications.

The tungsten-modified titanium dioxide, which prepared through the one-pot solvothermal process, exhibited the large specific surface area (~ 202 m2/g) and greater electrical conductivity (~ 0.022 S/cm). Furthermore, for the comparison purpose to find appropriate approach for the synthesis 20 wt. % Pt NPs/Ti0.7W0.3O2 catalyst, the modified chemical reduction utilizing NaBH4 and the rapid microwave-assisted polyol using ethylene glycol were employed without any surfactants or stabilizers. The characterization of Pt-based electrocatalyst was investigated through XRD, SEM-EDX, TEM measurements. As result, the platinum nanocatalyst formation with the face-centered cubic structure (fcc) and the amount loading on Ti0.7W0.3O2 support approximately 20 wt. % of two synthesized methods. However, the diameter size and distribution of Pt nanoforms have clearly classified in two reduction route. For example, the Pt nanocatalyst, which was created by the rapid microwave-assisted polyol at 160 °C for 2 min, exhibited the good distribution on support with ~3 nm diameter. This could be ascribed to the fast and uniform heating of microwave-assisted and moderate reducing possibility of ethylene glycol. These results indicate that the rapid microwave-assisted polyol was an appropriate approach not only for synthesizing 20 wt. % Pt NPs/Ti0.7W0.3O2 catalyst but also for preparing Pt-based electrocatalysts.

The materials currently used in proton-exchange membrane fuel cells (PEMFCs) require complex control of operating conditions to make them sufficiently durable to permit commercial deployment. One of the major materials challenges to allow simplification of fuel cell operating strategies is the discovery of catalyst supports that are much more stable to oxidative decomposition than currently used carbon blacks. Here, we report the synthesis and characterization of advanced nanostructure Ti0.7W0.3O2prepared via a low-temperature solvothermal process without using any surfactants or stabilizers. A promising doped metal oxide is a candidate for such a durable catalyst support. The synthesized nanoparticles were characterized by XRD, TEM measurements. Results show that Ti0.7W0.3O2exists in a single-phase solid solution with anatase phase of TiO2. Interestingly, the average particles size approximately 5 nm that could be promised to have a large specific surface area, which is an extremely important factor for promising catalyst support. Moreover, Ti0.7W0.3O2synthesized at 200 °C for 6 hours obtains the smaller particles size without particles agglomeration compared to previous researches. These results open a new approach for synthesis nanostructure Ti0.7W0.3O2by a solvothermal process for further application as catalyst support in PEMFCs.

Finding out robust active and sustainable catalyst towards alcohol electro-oxidation reaction is major challenges for large-scale commercialization of direct alcohol fuel cells. Herein, a robust Pt nanowires (NWs)/Ti0.7W0.3O2 electrocatalyst, as the coherency of using non-carbon catalyst support and controlling the morphology and structure of the Pt nanocatalyst, was fabricated via an effortless chemical reduction reaction approach at room temperature without using surfactant/stabilizers or template to assemble an anodic electrocatalyst towards methanol electro-oxidation reaction (MOR) and ethanol electro-oxidation reaction (EOR). These observational results demonstrated that the Pt NWs/Ti0.7W0.3O2 electrocatalyst is an intriguing anodic electrocatalyst, which can alter the state-of-the-art Pt NPs/C catalyst. Compared with the conventional Pt NPs/C electrocatalyst, the Pt NWs/Ti0.7W0.3O2 electrocatalyst exhibited the lower onset potential (~0.1 V for MOR and ~0.2 for EOR), higher mass activity (~355.29 mA/mgPt for MOR and ~325.01 mA/mgPt for EOR) and much greater durability. The outperformance of the Pt NWs/Ti0.7W0.3O2 electrocatalyst is ascribable to the merits of the anisotropic one-dimensional Pt nanostructure and the mesoporous Ti0.7W0.3O2 support along with the synergistic effects between the Ti0.7W0.3O2 support and the Pt nanocatalyst. Furthermore, this approach may provide a promising catalytic platform for fuel cell technology and a variety of applications.

Titanium dioxide (TiO2) has recently been used as a promising support for platinum (Pt)-based catalysts; however, its very low electrical conductivity and understanding the effect of the TiO2 structure on Pt electrocatalytic performance for ethanol electro-oxidation reaction (EOR) are major challenges in direct ethanol fuel cells. This study reports an easy and green approach to control the crystal structures of a robust iridium-incorporated TiO2 nanomaterial and its effect on the Pt electrocatalytic performance for EOR. A green hydrothermal route is used to fabricate iridium-modified TiO2 nanosupports with different structures by controlling the reaction temperature and time as well as solution pH without using further calcination, followed by the anchoring of Pt nanoparticles (NPs) via a surfactant-free modified reduction route. The experimental results indicate that the pure structure of the iridium-modified TiO2 nanosupport can easily be obtained by controlling the solution pH. In terms of EOR, all prepared catalysts show more effective performance than the commercial Pt/C catalyst. Among the prepared catalysts, the Pt anchored on the rutile iridium-incorporated TiO2 exhibits higher EOR performance than on the anatase iridium-incorporated TiO2 nanosupport, with negative onset potential, high current density, and electrochemical stability. The enhancement is assigned to the great adsorption and desorption ability as well as the high natural resistance to metal NPs ripening on (110) facets of the rutile structure compared with the (101) facets of the anatase structure. This exploration can offer an efficient route for tuning the structure of metal oxides and understanding the effect of the structure of the TiO2-based support on the Pt catalytic performance.

A series of Iridium (Ir)-doped strontium titanate (SrTiO3) was successfully prepared for the first time by a one-step heating hydrothermal method for water splitting applications. An amount of Ir was incorporated into SrTiO3 structure at 210 °C and pH = 13 without any surfactant or stabilization addition. Compared to the pure SrTiO3 nanomaterials, the as-obtained Ir-doped SrTiO3 photocatalysts shows the significantly improved hydrogen evolution under ultraviolet irradiation and the highest activity with a hydrogen evolution rate of 1376 μmol.g−1.h−1 of the Ir-doped SrTiO3 photocatalyst with very low amount of doping Ir (1.0 wt%). The X-ray photoelectron spectroscopy (XPS) analysis confirms the existence of Ir4+ in accompany with Ir3+ on the surface, which could be assigned for the excellent performance of prepared materials. The successful synthesis of Ir-doped SrTiO3 not only introduces a new route to prepare a promoting material for hydrogenation evolution from water splitting under ultraviolet (UV) irradiation using methanol as a sacrificed agent, but also creates a preliminary step for high-performance Ir-doped SrTiO3.