Palladium on carbon, commonly abbreviated Pd/C, is a heterogeneous catalyst made of metallic palladium dispersed across an activated-carbon support, typically loaded at 1 to 10 wt% palladium, most often sold as the 5% or 10% grade. Chemists use it to run hydrogenation, hydrogenolysis, debenzylation and Suzuki and Stille cross-coupling reactions, most commonly at just 1 to 4 atmospheres of hydrogen gas. Its composition, preparation, catalytic cycle, commercial grades and hazard classification follow below.
What Is Palladium on Carbon?#
Palladium on carbon is a supported heterogeneous catalyst, not a single molecular compound: fine particles of metallic palladium sit dispersed across the pore surface of an activated-carbon support, per Wikipedia's Palladium on carbon entry. It carries CAS number 7440-05-3, the registry number for palladium metal itself, because Pd/C has no single formula or molecular weight the way a discrete salt does, and PubChem holds no separate compound-level identifier for the mixture, the same handling class as platinum on carbon and Pearlman's catalyst.
| Property | Value |
|---|---|
| Preferred name | Palladium on carbon (Pd/C) |
| Composition | Metallic palladium dispersed on an activated-carbon support |
| CAS number | 7440-05-3 (identifies the palladium component, not a discrete Pd/C compound) |
| PubChem CID | None on record for the mixture |
| Typical Pd loading | 1-10 wt% Pd, most commonly 5% and 10% |
| Platinum group metal | Palladium (Pd), element 46 |
| Compound class | Heterogeneous hydrogenation and cross-coupling catalyst |
Palladium on carbon is one of the platinum group metal compounds and catalysts cataloged with a dedicated registry entry on this site.
Palladium on Carbon Structure and Bonding#
Palladium on carbon has no single coordination geometry or lattice type to report, because the catalyst is metallic palladium particles deposited on a carbon support rather than one bonded molecule. The palladium ends up in the zero oxidation state, Pd(0), the form the manufacturing route below produces by chemical reduction, per Wikipedia's Palladium on carbon entry, and that Pd(0) surface does the catalytic work described under Uses. Activated carbon is chosen for its high internal surface area, which spreads the palladium thinly enough to expose a large active surface for its weight.
PGM Content of Palladium on Carbon#
Palladium on carbon typically carries 1 to 10 wt% palladium, most commonly the 5% and 10% grades, a supplier-set loading range rather than one fixed percentage, per Wikipedia's Palladium on carbon entry, because Pd/C is a physical mixture, not a stoichiometric compound with a formula-derived metal content. For example, a hypothetical 10 g sample of the 10% grade contains close to 1 g of palladium and 9 g of carbon by weight, though the exact figure on any real lot varies with moisture in the water-wet grades and should come from its certificate of analysis.
Physical and Chemical Properties#
Palladium on carbon is a black powder whose palladium component dissolves in aqua regia while the carbon support remains chemically inert, per Wikipedia's Palladium on carbon entry. No single melting or decomposition point applies to the mixture as a whole, since Pd/C is metal particles on an inert support rather than one compound, but the dry, unreduced commercial grade (3 to 10% Pd, not yet fully reduced) carries a measured autoignition temperature of 120°C, per Acros Organics' safety data sheet (Thermo Fisher Scientific, rev. 30 April 2015). The standard, fully reduced catalyst instead ships water-wet, holding about 50 to 55% water by weight specifically to keep it below that ignition risk during storage and transport.
| Property | Value | Basis |
|---|---|---|
| Appearance | Black powder | Wikipedia's Palladium on carbon entry |
| Solubility | Palladium dissolves in aqua regia; carbon support is chemically inert | Wikipedia's Palladium on carbon entry |
| Melting or decomposition point | Not established for the mixture as a whole | Not applicable |
| Autoignition temperature, dry unreduced grade | 120°C | Acros Organics SDS, rev. 30 Apr 2015 |
| Typical Pd loading | 1-10 wt% Pd, most commonly 5% and 10% | Wikipedia's Palladium on carbon entry |
| Standard commercial form | Water-wet, about 50-55% water by weight, for fire safety | Multiple supplier SDS, including Flinn Scientific |
How Is Palladium on Carbon Made?#
Palladium on carbon is made by dissolving palladium(II) chloride in hydrochloric acid, combining that solution with activated carbon, then reducing the adsorbed palladium(II) to metal with formaldehyde, per Wikipedia's Palladium on carbon entry. The route runs in three steps:
- Dissolve palladium(II) chloride in hydrochloric acid.
- Combine the solution with activated carbon so palladium(II) adsorbs onto its pore surfaces.
- Reduce the adsorbed palladium(II) to metallic Pd(0) with formaldehyde, then filter and finish dry or water-wet at the target loading.
What Is Palladium on Carbon Used For?#
Palladium on carbon is used for heterogeneous hydrogenation, hydrogenolysis, debenzylation and Suzuki and Stille cross-coupling reactions, per Wikipedia's Palladium on carbon entry. Most hydrogenations run at just 1 to 4 atmospheres (15 to 60 psi) of hydrogen, though difficult substrates need up to 100 atmospheres, and ease of reduction follows acid halides, then alkynes, then alkenes, then ketones and aldehydes, then aromatic rings, per Master Organic Chemistry, which also notes more alkene double-bond migration on Pd/C than on platinum catalysts before hydrogenation completes. Three named uses cover the network:
- Hydrogenation and hydrogenolysis: reduces alkenes, alkynes and other unsaturated groups under hydrogen gas.
- Debenzylation: strips benzyl protecting groups from alcohols and amines under hydrogen, a routine deprotection step.
- Suzuki and Stille cross-coupling: forms carbon-carbon bonds between an aryl or vinyl halide and an organoboron (Suzuki) or organotin (Stille) partner, on the palladium sites below, covered further on this site's PGM catalysts in chemistry page.
Catalytic Cycle#
Palladium on carbon's cross-coupling activity runs through three steps, oxidative addition, transmetalation and reductive elimination, the mechanism behind the 2010 Nobel Prize in Chemistry awarded to Richard Heck, Ei-ichi Negishi and Akira Suzuki "for palladium-catalyzed cross couplings in organic synthesis," per the Nobel committee's press release.
- Add an aryl or vinyl halide (R-X) oxidatively across a palladium(0) site, forming an R-Pd-X intermediate.
- Transfer the organic group from an organoboron partner to palladium under basic conditions (transmetalation), displacing the halide.
- Eliminate reductively: the two organic groups couple to release the product and regenerate the palladium(0) site.
Commercial Forms, Purity and Price#
The standard commercial grade of palladium on carbon is a water-wet powder holding about 50 to 55% water by weight, sold mainly at 5% and 10% palladium loading, per Flinn Scientific's and other suppliers' safety data sheets. Major suppliers include Johnson Matthey and Alfa, Thermo Fisher, Sigma-Aldrich and Strem, and the water-wet form is standard because dry Pd/C is a recognized ignition source. Buyers track its price alongside DailyPlatinum's palladium price today page rather than a flat catalog rate.
| Grade | Pd loading | Form | Typical pack size class |
|---|---|---|---|
| Standard water-wet | 5% or 10% Pd | Water-wet powder, about 50-55% water | Gram to multi-kilogram, catalog and bulk |
| Dry, unreduced | 3-10% Pd | Dry powder, Pd(II) not yet fully reduced | Small research packs; a separate transport class (see Safety) |
| Dry, fully reduced | 1-10% Pd | Dry powder, spontaneously combustible | Specialty, low-moisture applications only |
Safety and Hazard Classification#
Palladium on carbon carries the GHS signal word Danger. GHS classification reported to PubChem: Danger; H228 (flammable solid), H315 (skin irritation), H319 (eye irritation), H335 (respiratory irritation), H413 (long-lasting harm to aquatic life). That covers the standard, fully reduced catalyst; the dry "unreduced" grade (3 to 10% Pd) carries a separate classification, Flammable Solid Category 2, signal word Warning, autoignition temperature 120°C, per Acros Organics' SDS (Thermo Fisher Scientific, rev. 30 April 2015), which also gives NFPA 704 ratings of Health 1, Flammability 2, Instability 0.
For transport, the standard water-wet catalyst ships as UN 2881, class 4.2 (spontaneously combustible), per HazMat Tool's entry; water and foam must never fight a Pd/C fire, since they can generate explosive hydrogen, so dry powder, alcohol-resistant foam or CO2 are used instead. The dry, unreduced grade ships under UN 3178, class 4.1, packing group III, per the same Acros SDS, which also lists incompatibility with strong acids, alcohols and halogens, and active listing on the US TSCA inventory and its Canadian, Philippine, Australian, Chinese and Korean counterparts.
Where Palladium on Carbon Chemistry Stops: Medical and Pharmaceutical Platinum#
This page covers palladium on carbon as a laboratory and industrial catalyst only, not as part of any platinum-based drug. Platinum-based pharmaceuticals such as cisplatin are named only as compounds elsewhere on this site, without dosing or side-effect detail; readers looking for that material should consult DailyPlatinum's platinum compounds page instead. No pharmaceutical use of palladium on carbon itself is documented in the sources checked here.
Related PGM Compounds#
Palladium on carbon shares its supported-catalyst design with two other named products on this site, distinguished by support and pretreatment.
| Compound | Support / composition | Relationship to palladium on carbon |
|---|---|---|
| Pearlman's catalyst | Palladium(II) hydroxide on carbon, Pd(OH)2/C | Same activated-carbon support family; introduced by William M. Pearlman, per Pearlman's original paper title, as a nonpyrophoric alternative that stays safe to handle dry, unlike plain Pd/C |
| Lindlar catalyst | Palladium on calcium carbonate, poisoned with lead | A different support, calcium carbonate rather than carbon, deliberately poisoned to stop hydrogenation at the alkene stage, unlike the unpoisoned, fully active Pd/C |
| Platinum on carbon | Platinum metal on activated carbon | Same activated-carbon support with platinum in place of palladium, favored for aromatic-ring and carbonyl hydrogenation |
Buyers needing the unsupported metal instead of a carbon-bound catalyst source palladium black, finely divided palladium without a support, for reactions that cannot tolerate residual carbon in the product.
History#
Catalytic hydrogenation over finely divided metals, the method behind the Pd/C family, traces to Paul Sabatier's work in the 1890s and 1900s, for which Sabatier shared the 1912 Nobel Prize in Chemistry, per Master Organic Chemistry. One of the earliest documented uses of a carbon-supported palladium catalyst was reported in 1914 by G. Verona-Rinati, who used a coke-supported palladium catalyst to hydrogenate oils without publishing quantitative data, per a secondary citation in Catalysis in Industry (Springer, 2022).
Frequently Asked Questions#
What is 10% Pd-C? The higher of the two most common commercial loadings, 10 wt% palladium on activated carbon, alongside the equally standard 5% grade.
What do H2 and Pd-C do? Together they hydrogenate alkenes, alkynes and other unsaturated groups, typically at 1 to 4 atmospheres of H2.
What is the chemical formula for Pd/C? None. It is a physical mixture of palladium on an inert carbon support, not a discrete compound; its CAS number, 7440-05-3, identifies the palladium component only.
Is Pd-C Lindlar's catalyst? No. Lindlar's catalyst uses calcium carbonate, not carbon, and is poisoned with lead to stop hydrogenation at the alkene stage, while Pd/C is unpoisoned and reduces alkenes to alkanes.
What does Pd-C stand for? Palladium on carbon, the shorthand for palladium dispersed on an activated-carbon support.
What are the downsides of using a palladium catalyst? Sulfur compounds such as thiophene bond strongly enough to a palladium surface to cut activity even at low concentrations, per a study in the Journal of Molecular Catalysis A: Chemical, and dry Pd/C is also a recognized ignition source, which is why suppliers ship it water-wet.