The Anode Hydrogen Release (AHR) mechanism at interfaces is responsible for the generation of defects, that traps charge carriers and can induce dielectric breakdown in Metal-Oxide-Semiconductor Field Effect Transistors. The AHR has been extensively studied at Si/SiO2 interfaces but its characteristics at metal silica interfaces remain unclear. In this study, we performed Density Functional Theory (DFT) calculations to study the hydrogen release mechanism at the typical Al/SiO2 metal-oxide interface. We found that interstitial hydrogen atoms can break interfacial Al-Si bonds, passivating a Si sp(3) orbital. Interstitial hydrogen atoms can also break interfacial Al-O bonds, or be adsorbed at the interface on aluminum, forming stable Al-H-Al bridges. We showed that hydrogenated O-H, Si-H and Al-H bonds at the Al/SiO2 interfaces are polarized. The resulting bond dipole weakens the O-H and Si-H bonds, but strengthens the Al-H bond under the application of a positive bias at the metal gate. Our calculations indicate that Al-H bonds and O-H bonds are more important than Si-H bonds for the hydrogen release process. (C) 2017 Elsevier B.V. All rights reserved.