The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core–shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.

http://repository.ust.hk/ir/bitstream/1783.1-77094/1/acs.chemrev.5b00462_withlink.pdf

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

More than 95% (in volume) of all of today’s chemical products are manufactured through catalytic processes, making research into more efficient catalytic materials a thrilling and very dynamic rese...

Metal–Organic Frameworks in Heterogeneous Catalysis: Recent Progress, New Trends, and Future Perspectives

Molecularly imprinted polymers are synthetic receptors for a targeted molecule. As such, they are analogues of the natural antibody–antigen systems. In this review, after a recounting of the early history of the general field, we specifically focus on the application of these polymers as sensors. In these applications, the polymers are paired with a reporting system, which may be electrical, electrochemical, optical, or gravimetric. The presence of the targeted molecule effects a change in the reporting agent, and a calibrated quantity of the target is recorded. In this review, we describe the imprinted polymer production processes, the techniques used for reporting, and the applications of the reported sensors. A brief survey of recent applications to gas-phase sensing is included, but the focus is primarily on the development of sensors for targets in solution. Included among the applications are those designed to detect toxic chemicals, toxins in foods, drugs, explosives, and pathogens. The application...

Molecularly Imprinted Polymers

A comprehensive review of recent advances in the field of oxygen reduction electrocatalysis utilizing nonprecious metal (NPM) catalysts is presented Progress in the synthesis and characterization of pyrolyzed catalysts, based primarily on the transition metals Fe and Co with sources of N and C, is summarized Several synthetic strategies to improve the catalytic activity for the oxygen reduction reaction (ORR) are highlighted Recent work to explain the active-site structures and the ORR mechanism on pyrolyzed NPM catalysts is discussed Additionally, the recent application of Cu-based catalysts for the ORR is reviewed Suggestions and direction for future research to develop and understand NPM catalysts with enhanced ORR activity are provided

Nonprecious Metal Catalysts for Oxygen Reduction in Heterogeneous Aqueous Systems

Abstract Electrochemical surface oxidation of carbon black Vulcan XC-72 and multiwalled carbon nanotube (MWNT) has been compared following potentiostatic treatments up to 168 h under condition simulating PEMFC cathode environment (60 °C, N2 purged 0.5 M H2SO4, and a constant potential of 0.9 V). The subsequent electrochemical characterization at different treatment time intervals suggests that MWNT is electrochemically more stable than Vulcan XC-72 with less surface oxide formation and 30% lower corrosion current under the investigated condition. As a result of high corrosion resistance, MWNT shows lower loss of Pt surface area and oxygen reduction reaction activity when used as fuel cell catalyst support.

http://ma.ecsdl.org/content/MA2005-02/33/1168.full.pdf

Durability Investigation of Carbon Nanotube as Catalyst Support for Proton Exchange Membrane Fuel Cell Electrode

On Capacity Upgradation and In Situ Capacity Rebalancing in Anthrarufin-Based Alkaline Redox Flow Batteries

Dye-sensitized solar cells are economical and easy to fabricate in comparison to silicon-based solar cells. The visible light sensitizer dye is the main component of DSSCs, the performance of which can be enhanced if the TiO2 semiconductor is engineered to maximize the utilization of the dye together with its easy regeneration from its oxidized form. In this study, a hierarchical porous architecture was imparted to the TiO2 photoanode using size-selected (1.5 to 3 nm) carbon nanomaterials (CNMs). This porous structure enhanced the accessibility of the dye to the electrolyte. Using the N719 dye as a model system, the effect of the hierarchical porous structure was demonstrated. The inclusion of CNMs together with TiO2 enhanced the short circuit current density by 31% and power conversion efficiency (PCE) by 46% compared to the CNM-free DSSCs.

/pdf/delineating-the-enhanced-efficiency-of-carbon-nanomaterials-41nwye4hd9.pdf

Delineating the enhanced efficiency of carbon nanomaterials including the hierarchical architecture of the photoanode of dye-sensitized solar cells

Iron-Dicyano Dichloro Quinone Primary Battery

Proton exchange membrane fuel cells (PEMFCs) have emerged as one of the most promising next-generation renewable energy technologies for the future. However, for the commercialization of PEMFC, low loading of Pt-based catalysts with suitable catalyst support is the utmost necessity. Pt alloys are useful for achieving good electrochemical activity with low Pt loading. But, high-temperature synthesis of these alloys leads to lower cyclic stability. Herein, we have synthesized Pt3Fe alloy on etched carbon nanotubes at low-temperature using oxygen-deficient Fe2O3-ECNT. This low-temperature synthesized Pt3Fe-ECNT shows excellent electrocatalytic activity due to the change in the d-band center and lattice contraction in the bimetallic alloy system. Lower hydrogen binding energy, increases in the electrochemical surface area (84 ± 3 m2 g–1) and mass activity (0.45 A mgPt–1) of the Pt3Fe-ECNT catalyst, compared to commercial Pt/C (0.36 A mgPt–1), confirms it to be a better catalyst for PEMFC. Furthermore, single-cell studies also show promising performance under real PEMFC conditions. A maximum power density of 530 mW cm–2 at 60 °C is achieved with Pt loading far lower than the U.S. Department of Energy (DOE) 2020 target (0.125 mgPt cm–2) with an excellent Pt catalyst utilization and fast kinetics. After an accelerated durability test of 10 000 cycles, stability studies substantiate it as a suitable catalyst for PEMFC applications. 

Low-Temperature Synthesized Pt3Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe2O3 as a Catalytic Center for PEMFC Applications

Kothandaraman Ramanujam

Papers

On Capacity Upgradation and In Situ Capacity Rebalancing in Anthrarufin-Based Alkaline Redox Flow Batteries

Delineating the enhanced efficiency of carbon nanomaterials including the hierarchical architecture of the photoanode of dye-sensitized solar cells

Iron-Dicyano Dichloro Quinone Primary Battery

Low-Temperature Synthesized Pt3Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe2O3 as a Catalytic Center for PEMFC Applications

Sustainable synthesis of hierarchically grown chloramphenicol‐imprinted poly(caffeic acid) nanostructured films