Publications by authors named "Samir H Al-Hilfi"

Single-atom catalysts (SACs) open up new possibilities for advanced technologies. However, a major complication in preparing high-density single-atom sites is the aggregation of single atoms into clusters. This complication stems from the delicate balance between the diffusion and stabilization of metal atoms during pyrolysis.

View Article and Find Full Text PDF
Article Synopsis
  • * The process involves the thermal decomposition of ligands, which modifies the distance between NPLs and affects their electronic coupling strength.
  • * Enhanced electronic coupling results in increased free carrier generation and improved short-range mobility, providing a clear method for optimizing NPLs for functional optoelectronic devices through thermal treatments.
View Article and Find Full Text PDF

Solution-synthesized graphene nanoribbons (GNRs) facilitate various interesting structures and functionalities, like nonplanarity and thermolabile functional groups, that are not or not easily accessible by on-surface synthesis. Here, we show the successful high-vacuum electrospray deposition (HVESD) of well-elongated solution-synthesized GNRs on surfaces maintained in ultrahigh vacuum. We compare three distinct GNRs, a twisted nonplanar fjord-edged GNR, a methoxy-functionalized "cove"-type (or also called gulf) GNR, and a longer "cove"-type GNR both equipped with alkyl chains on Au(111).

View Article and Find Full Text PDF

As the alternatives to expensive Pt-based materials for the oxygen reduction reaction (ORR), iron/nitrogen co-doped carbon catalysts (FeNC) with dense FeN active sites are promising candidates to promote the commercialization of proton exchange membrane fuel cells. Herein, we report a synthetic approach using perfluorotetradecanoic acid (PFTA)-modified metal-organic frameworks as precursors for the synthesis of fluorine-doped FeNC (F-FeNC) with improved ORR performance. The utilization of PFTA surfactants causes profound changes of the catalyst structure including F-doping into graphitic carbon, increased micropore surface area and Brunauer-Emmett-Teller (BET) surface area (up to 1085 m g), as well as dense FeN sites.

View Article and Find Full Text PDF
Article Synopsis
  • Chemical vapour deposition (CVD) is considered the best method for producing high-quality, large-area graphene sheets on transition metals, influenced by gas interactions and surface reactions.
  • A simulation of the CVD growth mechanism reveals that optimal graphene deposition occurs at high carbon-to-hydrogen ratios and around 850 °C, with no growth below this temperature due to insufficient carbon concentration.
  • The study highlights the importance of chamber geometry and gas phase composition in product concentration, and suggests that the developed thermodynamic and kinetic models can help design better reactors for varied graphene quality and potentially enable continuous production processes.
View Article and Find Full Text PDF