In Situ Structural Evolution and Activity Descriptor of Atomically Dispersed Catalysts During Nitrate Electroreduction.

Single-Atom Catalysts (SAC) have emerged as a promising class of materials for various catalytic applications, including the electrochemical nitrate reduction reaction (eNORR) and consequently ammonia production. While the efficiency and selectivity of these materials have been extensively highlighted for the eNORR, the in situ evolution to their structure and composition during electrocatalysis is largely unexplored and lacks catalyst design principles. To solve this, we investigated a series of high utilization metal-nitrogen-carbon (MNC) SACs (M = Cr, Fe, Co, Ni, and Cu) for eNORR.

Impact of N-heterocyclic amine modulators on the structure and thermal conversion of a zeolitic imidazole framework.

The zeolitic imidazole framework-8 (ZIF-8) is a crystalline porous material that has been widely employed as template to fabricate porous nitrogen-doped carbons with high microporosity thermal treatment at high temperatures. The properties of the carbon scaffold are influenced by the pore structure and chemical composition of the parent ZIF. However, the narrow pore size distribution and microporous nature from ZIF-8 often results in low mesopore volume, which is crucial for applications such as energy storage and conversion.

Influence of Commercial Ionomers and Membranes on a PGM-Free Catalyst in the Alkaline Oxygen Reduction.

Hitherto, research into alkaline exchange membrane fuel cells lacked a commercial benchmark anionomer and membrane, analogous to Nafion in proton-exchange membrane fuel cells. Three commercial alkaline exchange ionomers (AEIs) have been scrutinized for that role in combination with a commercial platinum-group-metal-free Fe-N-C (Pajarito Powder) catalyst for the cathode. The initial rotating disc electrode benchmarking of the Fe-N-C catalyst's oxygen reduction reaction activity using Nafion in an alkaline electrolyte seems to neglect the restricted oxygen diffusion in the AEIs and is recommended to be complemented by measurements with the same AEI as used in the alkaline exchange membrane fuel cell (AEMFC) testing.

Impact of ionomers on porous Fe-N-C catalysts for alkaline oxygen reduction in gas diffusion electrodes.

Alkaline exchange membrane fuel cells (AEMFCs) offer a promising alternative to the traditional fossil fuel due to their ability to use inexpensive platinum group metal (PGM)-free catalysts, which could potentially replace Platinum-based catalysts. Iron coordinated in nitrogen-doped carbon (Fe-N-C) single atom electrocatalysts offer the best Pt-free ORR activities. However, most research focuses on material development in alkaline conditions, with limited attention on catalyst layer fabrication.

Fe dissolution in Fe-N-C electrocatalysts during acidic oxygen reduction: impact of local pH change.

Atomic Fe in N-doped C (Fe-N-C) catalysts provide the most promising non-precious metal O reduction activity at the cathodes of proton exchange membrane fuel cells. However, one of the biggest remaining challenges to address towards their implementation in fuel cells is their limited durability. Fe demetallation has been suggested as the primary initial degradation mechanism.

Triazine-Based Graphitic Carbon Nitride Thin Film as a Homogeneous Interphase for Lithium Storage.

Triazine-based graphitic carbon nitride is a semiconductor material constituted of cross-linked triazine units, which differs from widely reported heptazine-based carbon nitrides. Its triazine-based structure gives rise to significantly different physical chemical properties from the latter. However, it is still a great challenge to experimentally synthesize this material.

Atomic metal coordinated to nitrogen-doped carbon electrocatalysts for proton exchange membrane fuel cells: a perspective on progress, pitfalls and prospectives.

Proton exchange membrane fuel cells require reduced construction costs to improve commercial viability, which can be fueled by elimination of platinum as the O reduction electrocatalyst. The past 10 years has seen significant developments in synthesis, characterisation, and electrocatalytic performance of the most promising alternative electrocatalyst; single metal atoms coordinated to nitrogen-doped carbon (M-N-C). In this Perspective we recap some of the important achievements of M-N-Cs in the last decade, as well as discussing current knowledge gaps and future research directions for the community.

Bioinspired and Bioderived Aqueous Electrocatalysis.

The development of efficient and sustainable electrochemical systems able to provide clean-energy fuels and chemicals is one of the main current challenges of materials science and engineering. Over the last decades, significant advances have been made in the development of robust electrocatalysts for different reactions, with fundamental insights from both computational and experimental work. Some of the most promising systems in the literature are based on expensive and scarce platinum-group metals; however, natural enzymes show the highest per-site catalytic activities, while their active sites are based exclusively on earth-abundant metals.

Metal coordination in CN-like materials towards dual atom catalysts for oxygen reduction.

Single-atom catalysts, in particular the Fe-N-C family of materials, have emerged as a promising alternative to platinum group metals in fuel cells as catalysts for the oxygen reduction reaction. Numerous theoretical studies have suggested that dual atom catalysts can appreciably accelerate catalytic reactions; nevertheless, the synthesis of these materials is highly challenging owing to metal atom clustering and aggregation into nanoparticles during high temperature synthesis treatment. In this work, dual metal atom catalysts are prepared by controlled post synthetic metal-coordination in a CN-like material.