# Electrocatalysis: templates > Electrocatalysts atom by atom, with computed polarization, Tafel and free-energy plots: water splitting, the OER mechanism, single-atom catalysts, CO₂ reduction on copper and gas-diffusion electrolyzers, Pt-alloy fuel-cell cathodes, MoS₂ edges, NiFe LDH, MOF-derived catalysts and benchmarking. URL: https://www.labcanvas.com/templates/electrocatalysis 10 templates. All templates: https://www.labcanvas.com/templates - [Water splitting: hydrogen and oxygen evolution](https://www.labcanvas.com/templates/electrocatalysis/water-splitting-her-oer-overpotential) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/water-splitting-her-oer-overpotential.md)): An electrolyzer splits water into hydrogen at the cathode and oxygen at the anode. Thermodynamics asks for 1.23 V, but each electrode adds an overpotential, and that is what catalysts cut. The common figure of merit is the overpotential at 10 mA cm⁻²; hydrogen evolution is fastest on catalysts that bind hydrogen neither too strongly nor too weakly. - [The OER mechanism: four proton–electron steps](https://www.labcanvas.com/templates/electrocatalysis/oer-mechanism-free-energy-diagram) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/oer-mechanism-free-energy-diagram.md)): Oxygen evolution on an oxide takes four proton–electron steps on one metal site, through HO*, O* and HOO*. Together they need 4.92 eV, 1.23 eV per electron; on a real catalyst the steps are uneven and the largest one sets the overpotential. Because HOO* and HO* bind together, oxides fall on one volcano, with a floor under their overpotential. - [Single-atom catalysts: one metal atom, four nitrogens](https://www.labcanvas.com/templates/electrocatalysis/single-atom-catalysts-co-n-c-zif-pyrolysis) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/single-atom-catalysts-co-n-c-zif-pyrolysis.md)): A single-atom catalyst spreads its metal as isolated atoms, each held by nitrogen in a carbon sheet, so every metal atom can be an active site. Pyrolysing a bimetallic Zn/Co framework does it: the linker turns into N-doped carbon, zinc evaporates above 800 °C, and cobalt stays behind as single atoms that reduce oxygen better than commercial platinum on carbon. - [CO₂ reduction on copper: many products](https://www.labcanvas.com/templates/electrocatalysis/co2-reduction-copper-c2-products) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/co2-reduction-copper-c2-products.md)): Most metals reduce CO₂ to one simple product: formate on tin, indium or lead, CO on silver or gold. Copper is the exception: it holds on to CO and couples carbons, making methane, ethylene, ethanol and a dozen more products, with hydrogen competing all the way. Which ones you get depends strongly on the potential. - [CO₂ electrolyzers: gas-diffusion electrodes](https://www.labcanvas.com/templates/electrocatalysis/co2-electrolyzer-flow-cell-gas-diffusion-electrode) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/co2-electrolyzer-flow-cell-gas-diffusion-electrode.md)): In an H-cell, CO₂ must dissolve before it reaches the catalyst, and that caps the current. Flow electrolyzers feed CO₂ as a gas through a gas-diffusion electrode right up to the catalyst, reaching more than 200 mA cm⁻². On copper at an abrupt interface in hydroxide, CO₂ became ethylene with 70% efficiency for 150 hours. - [Fuel cells: oxygen reduction on platinum alloys](https://www.labcanvas.com/templates/electrocatalysis/pem-fuel-cell-orr-pt3ni-platinum-skin) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/pem-fuel-cell-orr-pt3ni-platinum-skin.md)): A PEM fuel cell turns hydrogen and oxygen into water and electricity; the slow step is oxygen reduction at the platinum cathode. Alloying helps: Pt₃Ni(111), with a pure platinum skin over a nickel-rich layer, reduced oxygen 10 times faster than Pt(111) and 90 times faster than the Pt/C catalysts in use. - [MoS₂ for hydrogen: the edges do the work](https://www.labcanvas.com/templates/electrocatalysis/mos2-edge-sites-hydrogen-evolution) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/mos2-edge-sites-hydrogen-evolution.md)): Molybdenum disulfide is a cheap, layered alternative to platinum for making hydrogen, but only the edges of its layers are active: the flat basal plane hardly binds hydrogen. Counting the sites of MoS₂ nanoparticles showed activity rising in step with the number of edge sites, so MoS₂ catalysts are built to expose as many edges as possible. - [NiFe layered double hydroxides for oxygen evolution](https://www.labcanvas.com/templates/electrocatalysis/nife-ldh-oxygen-evolution-catalyst) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/nife-ldh-oxygen-evolution-catalyst.md)): Nickel–iron layered double hydroxides are the benchmark oxygen-evolution catalysts in alkaline water. Iron in the nickel hydroxide layers boosts activity by orders of magnitude, far more than its effect on conductivity explains; grown as ultrathin plates on carbon nanotubes, NiFe-LDH outperformed iridium. Even trace iron in the KOH electrolyte matters. - [MOF-derived catalysts: from framework to carbon](https://www.labcanvas.com/templates/electrocatalysis/mof-derived-fe-n-c-electrocatalysts) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/mof-derived-fe-n-c-electrocatalysts.md)): Heat a metal–organic framework and its linkers become nitrogen-doped carbon that often keeps the crystal’s shape, while its metals end up as single atoms held by nitrogen or as small particles. Iron catalysts made this way reduce oxygen without platinum: one matched a platinum cathode at 0.9 V, and isolated iron atoms beat commercial Pt/C. - [Benchmarking an electrocatalyst](https://www.labcanvas.com/templates/electrocatalysis/electrocatalyst-benchmarking-lsv-tafel-ecsa-eis) ([Markdown](https://www.labcanvas.com/templates/electrocatalysis/electrocatalyst-benchmarking-lsv-tafel-ecsa-eis.md)): To compare catalysts across labs, measure them the same way: in a three-electrode cell with a rotating disk, correct for the ohmic drop, report the overpotential at 10 mA cm⁻², the Tafel slope, the active surface area from the double-layer capacitance, the charge-transfer resistance, and how the potential holds over time.