Titrating　various　amount　of　graphene　nanoribbons　on　titanium　dioxide　nanotubes　(Gr/TNTs)　and　nano-bugles　(Gr/TNBs)　with　different　apertures　to　form　composite　nanostructures,　and　using　them　as　gas　sensing　layers,　have　been　achieved　successfully　and　confirmed　by　FESEM　observation,　Raman　spectra　comparisons,　XRD　and　FTIR　measurements.　The　Gr/TNBs　sensors　show　higher　hydrogen　gas　response　than　corresponding　Gr/TNTs　sensors　over　the　100–2000 ppm　range;　this　suggests　that　altering　sensing　morphology　can　improve　gas　sensing　capability.　A　composition　effect　is　found　on　Gr/TNBs　sensors,　and　this　effect　is　more　pronounced　with　higher　graphene　concentration.　On　the　other　hand,　heavier　graphene　content　on　Gr/TNTs　sensors　does　not　seem　to　affect　their　sensing　capability　much.　Also,　measuring　hydrogen　gas　sensitivity　under　fixed　gas　concentration　for　40 V　Gr/TNB　sensors　shows　a　strong　linear　correlation　between　graphene　concentration　and　responsivity.　Yet　measurement　on　40 V　Gr/TNTs　sensors,　at　relatively　low　gas　concentration　of　100 ppm,　shows　that　increase　in　graphene　content　hardly　affects　their　responsivity.　Gr/TNTs　sensors　fabricated　with　both　smaller　and　larger　tubular　apertures　produce　this　same　result,　too.　Lastly,　gas　diffusion　interactions　between　two-dimensional　layered　graphene　structure　and　various　geometries　of　TiO2　are　fully　discussed.　©　2022,　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature.