Javier Quílez-Bermejo

• Postdoctoral researcher
• Postdoctoral researcher at Paul Scherrer Institute

The coexistence of single atoms and nanoparticles is shown to increase the oxygen reduction performance in Fe‐N‐C electrocatalysts, but the mechanisms underlying this synergistic effect remain elusive. In this study, model Fe‐N‐C electrocatalysts with controlled ratios of FeN4 sites and Fe3C nanoclusters is systematically designed and synthesized....

Encapsulating Fe3C in carbon layers has emerged as an innovative strategy for protecting Fe3C while preserving its high oxygen reduction activity. However, fundamental questions persist regarding the active sites of encapsulated Fe3C due to the restricted accessibility of oxygen molecules to the metal sites. Herein, the intrinsic electron transfer...

Fuel cells (FCs) have emerged as a promising alternative for efficient electricity production in the future [1]. However, their widespread commercialization is hindered by their prohibitive cost due to the large amount of platinum used in these electrochemical systems [2]. Platinum is used to accelerate the unfavorable kinetics of the cathodic oxyg...

Nitrogen-doped carbon-based electrodes are among the most promising alternatives to platinum-based electrodes in the cathode of fuel cells and metal-air batteries, where the oxygen reduction reaction (ORR) takes place. Among the approaches for improving ORR activity, nitrogen functionalities and well-developed textural properties have proved very e...

In this study, efficient electrodes for the hydrogen evolution reaction (HER) based on low-cost and metal-free carbon catalysts are presented. Phytic acid, a biosourced molecule containing carbon (C) and phosphorus (P), was found to be an excellent precursor for producing carbon materials with high P content, depending on the carbonization temperat...

The sluggish kinetics and high overpotential of the oxygen reduction reaction (ORR) in fuel cells and metal–air batteries are currently resolved through the use of expensive and scarce platinum-based electrocatalysts. Here, a green and straightforward synthesis method for preparing metal-free phosphorus-doped carbon (PDC) materials via carbonizatio...

The sluggish kinetics of the oxygen evolution reaction (OER) is one of the most limiting factors for the development of many “green” electrochemical devices. Expensive ruthenium and iridium oxide electrodes are often used as advanced electrocatalysts to overcome this limitation. However, these materials are rare in nature, which further limit the i...

Single atoms and nanoclusters of Fe, Ni, Co, Cu, and Mn are systematically designed and embedded in a well‐defined C1N1‐type material that has internal cavities of ≈0.6 nm based on four N atoms. These N atoms serve as perfect anchoring points for the nucleation of small nanoclusters of different metal natures through the creation of metal‐nitrogen...

Platinum is considered the reference catalyst in many electrochemical devices such as electrolyzers or fuel cells. Nevertheless, the large-scale commercialization of these Pt-based devices is limited by the prohibitive cost of platinum as well as its quantity and availability. Regardless of its price and scarcity, it is well known that the oxygen r...

One of the biggest challenges in producing fuel cells at affordable prices is to synthesize carbon materials selectively doped with graphitic nitrogen, as it is considered the most active nitrogen species for the oxygen reduction reaction (ORR). So far, all strategies focus on the use of nitrogen-containing carbon precursors, which limits the funct...

Electrochemical water splitting requires new, low-cost cathode electrodes for the hydrogen evolution reaction to enable the worldwide implementation of electrolyzers. Cobalt borides are proposed as one of the most promising materials to overcome the limitations of the commercial electrocatalysts, but the catalytic activity still needs to be improve...

Oxygen reduction reaction (ORR) is one of the most important electrochemical reactions for fuel cells. However, commercial Pt-based catalysts used have important limitations such as their deactivation by carbon monoxide and Pt scarcity. In the present work, small and highly-dispersed copper and iron clusters were anchored onto composite supports ba...

Porous carbon materials are promising electrocatalysts for the oxygen reduction reaction (ORR). Their active sites, involving porosity and surface chemistry, are different from those of metal-doped carbons. The latter have been widely studied and are adapted to today's popular electrochemical devices, the rotating disk electrode being the most usef...

In the era of renewable technologies and clean processes, carbon science must adapt to this new model of a green society. Carbon materials are often obtained from petroleum precursors through polluting processes that do not meet the requirements of sustainable and green chemistry. Biomass is considered the only renewable source for the production o...

Electrochemical functionalization of Single-Walled Carbon Nanotubes and Herringbone Carbon Nanotubes (SWCNTs and hCNTs, respectively) has been successfully performed with aminophenylphosphonic acid isomers by potentiodynamic treatment in oxidative conditions. Exceptional selectivity...

Metal-free carbon-based electrocatalysts have arisen as groundbreaking alternatives to state-of-the-art electrocatalysts based on precious metals, leading to the industrial development and commercialization of environmentally friendly energy conversion and storage technologies. These novel materials have proved to be highly efficient and selective...

N-doped carbon materials have been considered one of the most promising options for the replacement of platinum-based electrocatalysts towards the oxygen reduction reaction (ORR). This work provides insights into the deactivation routes of N-doped carbon materials. The changes occurring in the active sites of N-doped carbon catalysts have been anal...

High-quality performance of catalysts is increasingly required to meet industry exigencies. However, chemical synthesis is often insufficient to maximize the potential properties of the catalysts. On the other hand, electrochemical synthesis has arisen as a promising alternative to overcome these limitations and provide precise control in the prepa...

Electrochemical functionalization of Single-Walled Carbon Nanotubes and Herringbone Carbon Nanotubes (SWCNTs and hCNTs, respectively) has been successfully performed with aminophenylphosphonic acid isomers by potentiodynamic treatment in oxidative conditions. Exceptional selectivity and control of the functional species embedded into the Carbon Nan...

Metal-free carbon-based catalysts have gained much attention during the last 15 years as an alternative toward the replacement of platinum-based catalysts for the oxygen reduction reaction (ORR). However, carbon-based catalysts only show promising catalytic activity in alkaline solution. Concurrently, the most optimized polymer electrolyte membrane...

An enzymatic metal-free electrochemical biosensor based on immobilized glucose oxidase on a N-doped porous carbon material has been studied for the detection of glucose in different real samples. The N-doped carbon material, which contains quaternary nitrogen groups, has been obtained by heat treatment of polyaniline. These functionalities promote...

One of the most challenging targets in oxygen reduction reaction (ORR) electrocatalysts based on N-doped carbon materials is the control of the pore structure and obtaining nanostructured thin films that can easily be incorporated on the current collector. The carbonization of nitrogen-containing polymers and the heat treatment of a mixture of carb...

Metal-free carbon-based catalysts have gained much attention during last years because of their interesting properties towards oxygen reduction reaction. Intrinsic parameters of carbon materials such as porosity, structural order, conductivity and defects have proved to have a strong influence in the catalytic activity of these materials. However,...

The sharp increase in current energy consumption needs the development of fuel cells (FCs) as one of sustainable, renewable, efficient and eco‐friendly electrochemical conversion systems of energy. The performance of electrocatalysts is crucially important for commercialization of FCs. Commercial Pt based catalysts are used due to their high cataly...

La Red AGEQI ha realizado la adaptación de materiales docentes para asignaturas de química. El principal objetivo del trabajo es aplicar los Principios del Diseño Universal (Connell et al., 1997) a la Instrucción (DUI) (Palmer, & Caputo, 2002-03) y al Aprendizaje (DUA) (Wakefield, 2008) para obtener materiales docentes de asignaturas con créditos p...

The design of advanced N-doped carbon materials towards oxygen reduction reaction (ORR) catalysis is only possible if the nature of the active sites is fully understood. There is an important piece of research seeking to overcome this challenge through experimental or theoretical results. However, the combination of both approaches is necessary to...

P-postmodified polyaniline was obtained by reacting phosphorus trichloride (PCl3) and chlorodiphenylphosphine (PPh2Cl) and polyaniline (PANI), under mild conditions. The reaction was found to be very selective, as only the imine groups were involved in the P-functionalization, and efficient as well, affording a P-loading of 3 at.% and 5 at.% for PP...

The development of electrocatalysts based on the doping of copper over cobalt spinel supported on a microporous activated carbon has been studied. Both copper–cobalt and cobalt spinel nanoparticles were synthesized using a silica-template method. Hybrid materials consisting of an activated carbon (AC), cobalt oxide (Co3O4), and copper-doped cobalt...

Polypyrrole (PPy) coatings inside the microporosity of an activated carbon fiber (ACF) were synthesized by chemical polymerization obtaining ACF-PPy composites. N-doped ACFs were prepared by carbonization of the ACF-PPy composites at two temperatures (500 and 800 °C). All the samples were characterized using different techniques (XPS, SEM, elementa...

Advanced catalysts for oxygen reduction reaction based on N-doped carbon materials have been designed by pyrolysis of polyaniline at temperatures above 1100ºC. The detailed characterization and computational calculations suggest that...

N-doped carbon materials were obtained using polyaniline (PANI) as precursor. Heat treatment of PANI and de-doped PANI (PANId) was performed using different temperatures −600 and 800 °C–. Two different atmospheres were used during the treatment: an inert atmosphere (N2) and another one consisting on a slightly oxidizing mixture of gases (3000 ppm O...