To　develop　various　strategies　to　prevent　the　aggregation,　sintering,　or　leaching　of　noble　metal　nanoparticles　(NPs)　represents　a　crucial　issue　for　efficient　synthesis　and　utilization　of　supported　noble　metal　NPs　with　highly　active　and　stable　catalytic　performance.　Here,　we　report　a　facile　synthesis　approach　to　obtain　a　Pd@hCeO2　hollow　core-shell　nanocomposite　that　is　composed　of　tiny　Pd　nanoparticles　cores　encapsulated　within　CeO2　hollow　shells.　The　core-shell　strategy　efficiently　prevents　the　aggregation　of　Pd　NPs　in　the　high　temperature　calcination　process　and　the　leaching　of　Pd　NPs　for　the　catalytic　reaction　in　a　liquid　phase.　This　anti-aggregation　and　anti-leaching　behavior　is　not　able　to　be　achieved　for　traditional　supported　Pd/CeO2　catalyst.　Such　a　Pd@hCeO2　composite　can　serve　as　an　efficient　multifunctional　nanocatalyst　in　both　heterogeneous　thermocatalytic　and　photocatalytic　selective　reduction　of　aromatic　nitro　compounds　in　water　under　ambient　conditions.　Each　component,　namely　Pd　metal　core　or　semiconductor　CeO2　shell,　makes　a　necessary　but　totally　dissimilar　reactive　contribution　to　achieving　the　same　end　product　during　these　two　different　catalytic　processes.　Importantly,　Pd@hCeO2　exhibits　an　excellent　reusable　and　much　higher　catalytic　performance　than　supported　Pd/CeO　2.　This　work　provides　a　generic　concept　example　on　inhibiting　aggregation　of　noble　metal　NPs　during　high　temperature　calcination　and　leaching　of　noble　metal　nanoparticles　into　solution　via　a　hollow　core-shell　strategy　and,　more　significantly,　on　sufficiently　harnessing　the　specific　metal　core　or　semiconductor　shell　function　integrated　in　a　core-shell　nanoarchitecture　toward　a　multifunctional　catalytic　use　in　both　thermocatalytic　and　photocatalytic　selective　green　transformation　in　water.　©　2013　American　Chemical　Society.