Disclosed is an unsupported bimetallic hydrogenation catalyst, its preparation and application thereof. The catalyst is composed of a complex formed by bonding a metal central atom or central ion with an organic ligand through a coordination bond, and has a schematic composition represented by formula (I): M.sup.1M.sup.2O.sub.a[R(COO).sub.x].sub.b (I), in which M.sup.1 and M.sup.2 represent metals, R(COO).sub.x represents an organic ligand, R represents the hydrocarbyl group of the organic ligand, COO represents the coordinating group of the organic ligand, x represents the number of coordinating groups in the organic ligand, a represents the molar ratio of oxygen atom linked to the metal via a non-coordination bond to the total amount of the metal, and b represents the molar ratio of the organic ligand to the total amount of the metal. When used for hydrogenation of hydrocarbons, the catalyst and composition thereof show high dispersibility in oil phase, high hydrogenation activity and high selectivity to target product.

A preparation method of a Co@CM multi-channel ceramic catalytic membrane for hydrogenation of p-nitrophenol is provided. In the catalytic membrane, a multi-channel ceramic membrane is adopted as a substrate. A cobalt salt as an active component is loaded in situ on a surface and in pores of the multi-channel ceramic membrane through a forced circulation with the help of the excellent reduction and anchoring effects of dopamine (DA), and then subjected to in situ self-reduction through calcination to produce the Co@CM multi-channel ceramic catalytic membrane. The preparation method has the following advantages: Nano-scale Co particles are loaded instead of a precious metal on a multi-channel ceramic membrane, and the surface of the Co particles is wrapped by carbon and nitrogen, which can effectively inhibit the loss of Co particles during a reaction. In addition, there is no need to add an additional reducing agent during the reduction of Co.

A preparation method of a Co@CM multi-channel ceramic catalytic membrane for hydrogenation of p-nitrophenol is provided. In the catalytic membrane, a multi-channel ceramic membrane is adopted as a substrate. A cobalt salt as an active component is loaded in situ on a surface and in pores of the multi-channel ceramic membrane through a forced circulation with the help of the excellent reduction and anchoring effects of dopamine (DA), and then subjected to in situ self-reduction through calcination to produce the Co@CM multi-channel ceramic catalytic membrane. The preparation method has the following advantages: Nano-scale Co particles are loaded instead of a precious metal on a multi-channel ceramic membrane, and the surface of the Co particles is wrapped by carbon and nitrogen, which can effectively inhibit the loss of Co particles during a reaction. In addition, there is no need to add an additional reducing agent during the reduction of Co.

The present invention provides microcapsules encapsulating hydrophilic or hydrophobic active agents in an inorganic shell, processes for their preparation and compositions comprising them.