Ahmed Yasin-Ali was chased down and killed in Elmfield Way, Maida Vale, by a group who fled in a car.
Offiers on Wednesday returned to the murder scene and appealing for anyone who has any information to contact them.
They distributed leaflets to the public on the street and anyone with information can either speak directly to officers or get in touch online or by phone.
Seven men aged between 17 and 38 have been arrested in connection with the case and released under investigation.
Detective Chief Inspector Vicky Tunstall, said: “Ahmed’s murder took place close to Harrow Road which is a busy arterial road through west London. Do you remember driving through Harrow Road on the night of the murder? Did you see a blue Mazda 2 GT Sport, with a registration of LD17 CXS, leaving the area at speed at around half-past midnight?
“The passing of a year since Ahmed’s death has been torture for his loved ones, but I am hoping that, during these long months, someone will have been told something about the events of that night, or may have heard something about who was responsible, and I urge anyone who has information to take the next step and come forward and speak to us. You may even be eligible for a substantial reward for your assistance.”
A police statment said: “A murder investigation was launched on 15 July 2020 after the teenager was found with stab injuries on Elmfield Way, W9, at approximately 00:30hrs.
“Officers provided first aid prior to the arrival of the London Ambulance Service (LAS) and London’s Air Ambulance. Ahmed was taken by LAS to a central London hospital where he died at 01:06hrs.”
Anyone with information is asked to call police via 101 or Tweet @MetCC quoting reference CAD 185/15Jul20.
To remain anonymous call Crimestoppers on 0800 555 111.