NOVELTY - Catalyst, comprises: a disordered array of nanostructures; and many metal-containing nanoparticles attached to the nanostructures to form a disordered array of metallized nanostructures.    USE - The catalyst is useful in: catalyzing a reaction; catalysis device; for producing hydrogen; and for storing hydrogen for use in generating energy (all claimed). The device is useful as part of the operation of an energy-consuming device or system, e.g. an engine and a fuel cell. The methods are useful in hydrogenation, dehydrogenation and polymerization reactions. The catalyst is useful to catalyze oxidation reactions and for the catalytic reaction of various liquids and/or gases to produce carbon dioxide and hydrogen and/or a reduced organic molecules (e.g. a water gas shift reaction).    ADVANTAGE - The catalytic activity and/or selectivity of the catalysts can be modified or tuned to catalyze specific chemical reactions by selecting: the size of the accessible catalytic sites in the macroporous network; at least the identity of one of the metals contained in the nanoparticles and the average cross-sectional dimension of the nanoparticles; and the compositions of the nanoparticles and nanostructures where there is an electronic interaction between the nanostructures and the nanoparticles. The catalyst releases hydrogen in a controlled manner for use as fuel.    DETAILED DESCRIPTION - Catalyst, comprises: a disordered array of nanostructures; and many metal-containing nanoparticles attached to the nanostructures to form a disordered array of metallized nanostructures, where: an average cross-sectional dimension of the nanoparticles is at most about half an average cross-sectional dimension of the nanostructures; the disordered array of metallized nanostructures provides a macroporous network comprising accessible catalytic sites; and a catalytic activity of the catalyst is tuned by adjusting a size of the accessible catalytic sites in the macroporous network and adjusting at least one of a metal contained in the nanoparticles and the average cross-sectional dimension of the nanoparticles. INDEPENDENT CLAIMS are included for:    (1) a method of catalyzing a reaction, comprising: selecting a size of accessible catalytic sites in a macroporous network that can adsorb one or more reactants in a catalyzed reaction, where the macroporous network is formed by a disordered array of nanostructures and many of metal-containing nanoparticles are attached to the nanostructures; and selecting at least one of an average cross-sectional dimension of the nanoparticles and a composition of the nanoparticles to catalyze the reaction;    (2) a catalysis device, comprising: a disordered array of nanostructures, where the nanostructures comprises a wide bandgap semiconductor material; and many of metal-containing nanoparticles disposed on the nanostructures to form a disordered array of metallized nanostructures providing a macroporous network with accessible catalytic sites;    (3) a method for manufacturing a catalysis device, comprising: forming a disordered array of nanostructures comprising a wide bandgap semiconductor material; and disposing many metal-containing nanoparticles on the nanostructures to form a disordered array of metallized nanostructures to provide a macroporous network with accessible catalytic sites;    (4) a method of producing hydrogen, comprising: either exposing an oxygen catalysis device to carbon monoxide in an enclosure, where the oxygen catalysis device comprises a nanostructure comprising a wide bandgap semiconductor material and many metal-containing nanoparticles disposed on the nanostructure; evacuating carbon monoxide from the enclosure; and after evacuating carbon monoxide from the enclosure, introducing a molecule comprising hydrogen and oxygen to the oxygen catalysis device to produce hydrogen; or providing a nanostructured catalyst comprising metal-containing nanoparticles disposed on a substrate and/or on a disordered array of nanostructures; reacting a compound of formula (R1-XH) (a) capable of generating hydrogen with the nanostructured catalyst to produce hydrogen gas and a compound of formula (R1-X) (gt) bound to the nanostructured catalyst and/or a dehydrogenated spent compound; and collecting the hydrogen gas; and    (5) a method for storing hydrogen for use in generating energy, comprising: providing a nanostructured catalyst comprising metal-containing nanoparticles disposed on a substrate and/or disordered array of nanostructures; reacting a dehydrogenated compound with hydrogen gas with the nanostructured catalyst to produce a compound having (a); and collecting (a).    R1 = moiety, which is an alkenyl (optionally substituted), alkyl, heteroalkyl, alkynyl, aryl, heteroaryl, alkoxy, cycloalkyl, heterocyclic, alkylaryl, arylalkyl, arylalkenyl, arylalkynyl, arylene and/or oxyarylene; and    X = S, O or Se.