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Many times I have seen the catalyst as Raney nickel instead of nickel catalyst. Raney nickel catalyst is developed by Murray Raney, and I think Raney nickel catalyst and nickel catalyst are two different things, because various sources use both names.

How do they differ from each other?

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    $\begingroup$ Raney nickel is derived from a nickel-aluminum alloy. The removal of the aluminum results in a higher surface area for the Raney nickel vs regular nickel. $\endgroup$ – Brinn Belyea Jul 28 '14 at 15:46
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Yes, the Raney nickel catalyst is different from simple, fine nickel powder. Raney nickel is prepared in two steps. First, the nickel is alloyed with aluminum and then in second step much of the aluminum is removed through a leaching process with sodium hydroxide. As the aluminum is removed two things happen. The resulting nickel-aluminum alloy becomes very textured and porous with extremely high surface area (sponge-like). Also hydrogen gas is liberated during the leaching process and some of it remains adsorbed on the alloy surface. This is the active catalyst that is ready for use.

$$\ce{2 Al + 2 NaOH + 6 H2O -> 2 Na[Al(OH)4] + 3 H2}$$

If you'd like to read more about the initial alloying process or the activation (leaching) step, see this Wikipedia article.

As an aside, Murray Raney discovered this catalyst (US1628190) in the late 1920's and he was the sole assignee. I'm guessing that W. R. Grace bought the patent rights from him since they hold the trademark on use of the term "Raney nickel"

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    $\begingroup$ As pointed out by ron, a large surface is the key. Another Ni-based catalyst is prepared by 1. reducing a Ni salt with zinc and then treating the resulting mixture with A) acid or B) base. The resulting catalysts are known as Urushibara nickel (type A and B, resp.) $\endgroup$ – Klaus-Dieter Warzecha Aug 19 '14 at 6:40
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    $\begingroup$ Ron, spot on with the Raney trademark comment. It's as simple as that. Any nickel catalyst prepared in the manner above, not from Grace, is sponge nickel $\endgroup$ – Beerhunter Aug 9 '17 at 6:36

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