The localization of photoexcitation leads to the proximity of photocatalytic reduction and oxidation sites, causing unfavorable side reactions. To address this issue, we designed a double-walled nanotube model system consisting of carbon nanotube (CNT) outside and carbon-nitride nanotube (CNNT) inside, with physically close yet chemically separate reduction and oxidation sites for safe photocatalytic hydrogen generation. First-principle calculations show that photoexcited charges in the system rapidly separate, leaving electrons at the reductive sites in CNNT and holes at the oxidative sites in CNT, respectively. Then protons generated by hole-assisted water dissociation at the CNT migrate to the CNNT and are reduced, producing H2. The selective permeability of protons through CNT ensures complete separation of hydrogen molecules and oxygen species, and thereby the reduction and oxidation half-reactions. Further, H2 products can be delivered via the double-walled nanotube for safe collection. The seamless integration of photocatalytic hydrogen generation and delivery in one system provides an alternative solution toward practical solar-driven hydrogen utilization.