Catalysts, supported catalysts and hydrogen storage materials exhibiting quantum effects. The disclosed quantum limit catalyst is comprised of atomic aggregations whose dimensions correspond to the quantum limit. The structural configurations possible in the quantum limit correspond to atomic aggregations having bond lengths, bond angles, topologies and coordination environments that differ from those found in the macroscopic limit. The modifications in election density and wavefunction characteristics (overlap and directionality) achieved in the quantum limit provide, in effect, 'new' or 'virtual' chemical elements whose structure and bonding deviate from those associated with the 'standard' chemical elements of conventional materials. A catalyst including a catalytic phase supported by an electronically active support matrix is further disclosed. An electronic interaction that occurs between the catalytic phase and support matrix leads to perturbations in the magnitude and/or spatial distribution of electron density at or near the surface of the catalytic phase. The electronic interaction originates from an overlap of wavefunctions associated with electron density of the catalytic phase with wavefunctions associated with electron density of the catalytic phase. Embodiments include those in which the electronic interaction is of the bonding-type, anti-bonding type or donor-acceptor type. Filled, partially filled or unoccupied orbital states may participate in the electronic interaction. The perturbation in electron density induced by the electronic interaction modifies the catalytic properties of the catalytic phase.