Download or read book Metal-free Heteroatom Doped-Carbon Nanomaterials for Energy Conversion and Storage written by MIN. WANG and published by . This book was released on 2017 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel cell is considered as one of the most environmentally friendly devices for sustainably converting chemical energy to electricity. Till now, its large-scale application has been hindered by the high-cost of platinum catalysts required for oxygen reduction reaction (ORR) at the cathode. Although the amount of noble metal needed for the desired catalytic effect could be reduced by using nonprecious-metal catalysts, they are still too expensive for the commercial mass production of clean energy, or their energy conversion efficiency is too low. Owing to the related low cost, large surface area, high electrical conductivity, rich electrocatalytic active sites, and corrosion resistant properties, a new class of carbon-based, metal-free catalysts has been developed which could dramatically reduce the cost and increase the efficiency of fuel cells when used as alternative ORR catalysts. For example, various heteroatom-doped carbon nanomaterials have been developed as efficient metal-free catalysts for ORR. However, their performance still needs to be further improved to pave the way for technological advancement, particularly in the proton exchange membrane fuel cell (PEMFC). Another problem is that most of the ORR studies on carbon-based electrocatalysts have been conducted using a half electrochemical cell with alkaline medium, the electrochemical performance of carbon-based metal-free nanomaterials in acidic medium is rarely, let alone the single fuel cell. In this study, various metal-free carbon-based catalysts have been developed by rational heteroatom doping coupled with super advanced structures (by intrinsic and macroscopic tune). Different units, including carbon nanotubes (CNTs), graphene, graphitic carbon nitrides, and biomass, were selected for constructing novel carbon-based nanomaterials with highly porous structure and abundant electrochemically active sites. Heteroatoms doped or co-doped carbon nanotubes (B,N-CNT and N,F-CNTs) , carbon nitride decorated nitrogen doped graphene (C3N4@N-G) composites, N-doped graphene/CNT hybrids (N-G-CNT), and N-doped hierarchical porous carbon have been successfully developed as high efficient catalysts. The ORR performances of these carbon-based catalysts were investigated in three-electrode electrochemical setup in both alkaline and acidic mediums. PEMFCs utilizing the carbon-based catalysts as cathode catalyst for ORR were also fabricated and studied in detail. Especially, the rationally designed N-G-CNT exhibited excellent catalytic activities and selectivity for ORR, even with good single cell performance.